Listed below are three categories with brief descriptions of Congestion Management Strategies which can be used to reduce congestion and/or mitigate some of its negative consequences.

Roadway Operational Improvements

• Geometric Changes and Bottleneck Alleviation
  • Such strategies include the addition or reconfiguration of turning lanes, lane widening, realignment of intersecting streets, improved acceleration or deceleration lanes at interchange ramps. Removal of a physical constriction that delays travel, such as widening an underpass, providing lane continuity (i.e., replacing a two-lane bridge that connects pieces of four-lane roadway), or eliminating a sight barrier. Such strategies may be applied to highways, arterials, or local streets.
    Impact on Congestion — These strategies are most able to make a difference for congestion caused by an isolated misallocation of road space or a similar engineering problem. Remedying these problem situations can help make the most of existing road capacity and improve overall traffic flow. For instance, studies show that nearly half of weekday, peak-period congestion delay on California highways occurs at 600 recurrent bottlenecks. ¹ However, geometric changes to promote vehicle flow on arterials and local streets can potentially have negative consequences for alternative modes competing for the same space. Furthermore, none of these sorts of strategies encourage higher vehicle occupancy nor discourage peak-hour vehicle use.
    Financial Cost — Variable, depending on the project.
• Access Management
  • Access management includes policies, design criteria, and facilities that minimize the number of driveways and intersecting roads accessing a main thoroughfare, including parallel service roads, shared driveways, median barriers, and curb cut limitations.
    Impact on Congestion — Access management can result in fewer accidents, higher average vehicle speeds, and more vehicle throughput per level of service (LOS). For instance, decreasing the number of signalized intersections from 3 to 2 per mile increases vehicle speeds by 9 percent; employing U-turns instead of dual left turns can increase capacity by 15 to 20 percent; and a four-lane road with high access management can accommodate 42 percent more vehicles per day at LOS D than one with low access management. ² Access management strategies sometimes complement the needs of pedestrians and bicyclists, such as reducing the number of driveway cuts across a sidewalk, but in other situations could have negative consequences for these modes, such as by reducing the number of signalized crossings and increasing exposure to higher-speed traffic. Conventional access management strategies do nothing to encourage higher vehicle occupancy or to discourage peak-hour vehicle use.
    Financial Cost — The cost is variable, depending on the project.
    Additional Resources
    • Access Management Section of the FHWA Office of Operations
    • Access Management Manual published by the TRB, 2003
    • Website for the TRB Committee on Access Management AHB70
    • NCHRP Report 548 “A Guidebook for Including Access Management in Transportation Planning,” 2005
    • Access Management: Expanding the Congestion Management Toolkit," 2003
• Traffic Signalization and Control
  • Control systems vary in the extent that they adapt to current conditions and in the extent that they synchronize with a larger signalized network. For instance, signals may be pre-timed and isolated, pre-timed and synchronized, actuated by events such as the arrival of a vehicle, pedestrian, bus, or emergency vehicle, set to adopt one of several pre-defined phasing plans based on current traffic conditions, or set to calculate an optimal phasing plan based on current conditions.
    Impact on Congestion — Good signal timing can greatly reduce delay at intersections, although more complex systems do not always produce better results. On the other hand, some regions have used signal control and coordination to gain up to 29 percent reduction in travel time and up to 56 percent reduction in stop time. ³ Such systems may be part of an overall program of Active Traffic Management. Systems with transit signal priority have reduced transit travel times by up to 42 percent, delay by up to 48 percent, variability by up to 59 percent, and have improved on-time arrival by up to 58 percent, although sometimes at the expense of other vehicles, found to have around 3 percent more delay. ⁴ Such systems clearly encourage high-occupancy transit use. Signals can also be used to better accommodate pedestrian and cyclists at intersections, but signal phasing that maximizes vehicle throughput may do so at the expense of these other modes. In general, signal phasing that reduces vehicle delay does nothing to discourage peak-hour vehicle use.
    Financial Cost — The cost ranges from $2,000 to $108,000 per intersection in capital costs, depending on the sophistication of the system. For instance, signal controller upgrades cost $2,400 to $6,000; signals themselves cost $90,000 to $108,000; and equipment such as a signal preemption receiver costs $2,000 to $6,000 each. LAN connections may cost an additional $23,000 and $55,000. ⁵ Additional cost need to be considered for operating and maintaining the control system as well.
    Additional Resources
    • Website for the TRB Committee on Access Management AHB70
    • ITS Benefits, Costs, and Lessons Learned Databases Website
    • Traffic Signal Control Section of the ITS Decision website
    • “Traffic Signal Operations Self Assessment” on the ITE website
    • “Traffic Signal Audit Guide” by National Transportation Operations Coalition and ITE
    • ITS America report, “An Overview of Transit Signal Priority,” 2004
    • ITS America report, “Transit Signal Priority (TSP): A Planning and Implementation Guide,” 2005
    • U.S. DOT, ITS Joint Program Office, “Intelligent Transportation Systems for Traffic Signal Control” leaflet, Publication No. FHWA-JPO-07-004, 2007
• One-Way Streets
  • This approach establishes or removes, pairs of one-way streets in place of a standard two-way street. This could include modifying the one-way or two-way nature of side streets in order to impact traffic patterns on a mainline corridor. Systems of one-way streets facilitate signal synchronization and can reduce the need for disruptive right- and left-hand turns, thus enabling higher speeds and more capacity along arterials.
    Impact on Congestion — Studies have shown that converting two-way streets to one-way streets results in fewer stops (up to 60 percent), increased average speeds (up to 37 percent), and increased volumes of vehicle traffic (up to 19 percent). ⁶ While there are generally fewer accidents on one-way streets (including those involving pedestrians), seemingly due to simpler intersection designs, it is also possible that higher volumes of faster traffic make streets more dangerous for pedestrians and cyclists. In addition, one-way streets do nothing to encourage higher vehicle occupancy and to discourage peak-hour vehicle use.
    Financial Cost — Costs include those associated with striping, adjusting signal phasing, and signage.
    Additional Resources“One-Way Streets Provide Superior Safety and Convenience,” by J. Stemley, in ITE Journal, 1998.
• Reversible Lanes
  • In a reversible lane in which traffic may travel in either direction, depending on conditions. Direction of flow may be established using signals, signage, or pavement markings, also called counter flow, tidal flow, or contra flow lanes.
    Impact on Congestion — Before/after studies conducted in the 1960s and 1970s show that peak-hour traffic volume increased 7 percent, travel times decreased up to 25 percent, and average vehicle speed increased 22 percent using reversible lanes. Such lanes are thought to be most effective in addressing recurrent and predictable congestion, on routes with a directional imbalance in excess of 65/35 percent, with a predominance of through traffic. Contrary to popular belief, reversible lanes are not associated with increased traffic incidents. ⁷ Reversible lanes generally do nothing to encourage higher vehicle occupancy or to discourage peak-hour vehicle use.
    Financial Cost — Reversible lanes can often be implemented “with minimal capital cost, particularly on segments such as tunnels and bridges, where the cost of adding new lanes would be very high if not impossible.” ⁸ In general, costs are variable, depending on the project.
    Additional Resources
    NCHRP Synthesis 340, “Convertible Roadways and Lanes: A Synthesis of Highway Practice,” 2004
• Hard Shoulder Running
  • Hard shoulder running uses the shoulder as a travel lane during congested periods or allows traffic to move around an incident. Use of the lane may be general purpose or restricted, such as to transit vehicles.
    Impact on Congestion — An 11-mile trial segment in the UK produced a 25 percent reduction in travel time. ⁹ Temporary shoulder use in the Netherlands increased overall capacity up to 22 percent, decreased travel time, and increased traffic volumes up to 7 percent during congested periods. ¹⁰ Effectively a form of capacity expansion, hard shoulder running does nothing to discourage peak-hour vehicle use. However, if restricted to transit or HOV use, it serves to encourage higher vehicle occupancy and enables more efficient transit operations.
    Financial Cost — By using existing roadway, shoulder running adds lane capacity for much less than the cost of adding a new lane. Additional costs may be incurred by features such as signage, striping, construction of refuge spots, and dynamic speed control. An 11-mile segment in the UK cost £100 million in 2006 versus an estimated £500 million to construct a new lane. ¹¹
    Additional Resources
    • FHWA Report No. FHWA-PL-07-012, “Active Traffic Management: The Next Step in Congestion Management,” 2007
• High-Occupancy Vehicle (HOV) Lanes
  • High occupancy vehicle lanes are reserved for vehicles containing at least a specified number of occupants (such as 2, 3, 4, or more) or for transit vehicles-also known as carpool lanes, commuter lanes, diamond lanes, or bus lanes. Such lanes can be on highways, on arterials, or on metered entrance ramps to highways. They may be physically separated from other lanes, or indicated with signage. Some operate only during certain hours. Other types of strategies discussed elsewhere in this report that potentially promote higher vehicle occupancy include ridesharing programs, parking management, guaranteed ride home policies, and other employer-based programs.
    Impact on Congestion — During the peak hour, most HOV facilities carry more people per lane than do adjacent general purpose (GP) lanes, especially those with high bus volume, making them a more efficient use of scarce road space. ¹² They have been especially successful in Washington State. Furthermore, surveys indicate that a quarter to a half of HOV users nationwide previously drove alone (although this share is thought to be less in areas with casual carpooling), suggesting that HOV lanes have had some impact on travel choices, having induced an increase in average vehicle occupancy by 8 percent, on average. ¹³ HOV lanes have not been shown to decrease overall congestion, however, in part because they have been implemented in places with rapid VMT growth, and also because the majority of lanes do not enjoy their benefits. They do diminish congestion delay and increase travel time reliability for the high occupancy and transit vehicles utilizing them, providing greater incentive to use these modes. This incentive is larger when the GP lanes are more congested relative to the HOV lanes.
    Financial Cost — Construction costs for adding new lanes on urban highways costs from $6 to $13 million per lane mile on expressways and $2 to $5 million per lane mile on undivided highways (in 1997 dollars). ¹⁴ Restriping existing lanes costs considerably less, at about $100,000 per lane mile. Maintenance and enforcement are additional costs to consider.
    Additional Resources
    • High Occupancy Vehicle Facilities section of the FHWA website
    • TCRP Report No. 95, “High Occupancy Vehicle Facilities: Traveler Response to Transportation System Changes,” 2006
    • TCRP Report No. 95, Traveler Response to Transportation System Changes, “Chapter 2 ? HOV Facilities,” 2006
    • What we’ve learned about highway congestion," by Pravin Varaiya in Access No. 27, 2005
    • High-Occupancy Vehicle Facilities" section of the ITS/Operations Resource Guide 2007 website
    • Victoria Policy Institute’s Victoria Policy Institute’s TDM Encyclopedia entry on HOV Priority
    • Washington State Freeway HOV System section of the WSDOT website
    • FHWA Report No. FHWA-HOP-05-037, “Managed Lanes: A Cross-Cutting Study,” 2004
    • Website for Northern Virginia commuters demonstrating potential travel time savings using HOV lanes
• Ramp Metering
  • Ramp metering uses signals at points where ramps enter a freeway, which regulate the rate and spacing of traffic entering the freeway based on actual conditions. More broadly defined, the concept of “junction control” refers to the use of variable traffic signs, dynamic pavement markings, and lane use control to direct traffic to specific lanes (mainline or ramp) based on varying traffic demand.
    Impact on Congestion — Ramp metering has been shown to produce increased throughput (up to 30 percent on freeways, 20 percent on arterials), decreased delay (up to 36 percent), increased vehicle speed (up to 60 percent), decreased travel time (up to 16 percent), and a decreased incidence of crashes (up to 50 percent). ¹⁵
    Financial Cost — Capital costs are $24,000 to $49,000 per meter, plus additional costs for sensors, communications wireline, and other equipment, if necessary, as well as for maintenance and operations. ¹⁶ Communication medium connecting ramp meters can represent a major part of the cost. ¹⁷
    Additional Resources
    • FHWA Report No. FHWA-HOP-06-001, “Ramp Management and Control Handbook,” 2006
    • Ramp Metering" section of the ITS Benefits, Costs, and Lessons Learned Databases website
    • Ramp Metering, section of the ITS Decision website
• Road Pricing
  • Toll roads, cordon pricing, congestion pricing, and high-occupancy toll (HOT) lanes are all forms of road pricing that charge motorists for driving on a particular roadway or zone. While road and cordon tolls are usually flat rates (perhaps variable by time of day), congestion pricing levies higher fees when there is more traffic, which is either determined dynamically or by time of day. HOT lanes are HOV lanes that permit free use by high-occupancy vehicles and paid use by all others.
    Impact on Congestion — The impact of pricing on congestion can vary greatly depending on the type of pricing scheme. Tolls designed to be the minimum to cover costs may do little to influence traveler behavior and reduce congestion. Expanding the scope of HOV lanes to HOT lanes can help increase traffic volumes on underutilized HOV lanes, while keeping volumes below congested levels through proper pricing. However, as with all HOV lanes, they provide limited benefits to the facility as a whole. By contrast, congestion pricing has been overwhelmingly successful in stemming congestion on facilities that implement it. For instance, time-of-day cordon pricing in downtown London has been found to reduce delay by 30 percent, reduce bus delay by 50 percent, and increase vehicle speeds by 37 percent. Congestion pricing on Singapore’s highways has resulted in a 13 percent decline in peak-hour traffic and a 20 percent increase in speeds. ¹⁸ The better the available alternatives to peak-hour vehicle use, the greater the potential impact of road pricing on congestion, and fewer potential negative impacts of road pricing on residents’ mobility. Some research suggests that congestion pricing is the most likely, if not only, means of successfully managing congestion. ¹⁹
    Financial Cost — Toll and pricing facilities impose capital costs (for lanes, signage, transponders, and other electronics), in addition to costs associated with operations, maintenance, and enforcement. For instance, electronic toll readers may cost $2,000 to $5,000 per lane, high-speed cameras $7,000 to $10,000 per camera (perhaps serving two lanes), and software $5,000 to $10,000.20 London’s congestion pricing system required an outlay of $353 million in capital costs, in addition to about $176 million annually in operating costs. ²¹ However, because the costs associated with all pricing programs are covered by the revenues collected, their net fiscal impact is revenue-generating.
    Additional Resources
    • Tolling and Pricing section of the ITS/Operations Resource Guide 2007
    • Tolling and Pricing section of the FHWA website
    • FHWA Report No. FHWA-HOP-07-074, “Congestion Pricing: A Primer,” 2006
    • FHWA’s Urban Partnerships Program website
    • TCRP Report No. 95, Traveler Response to Transportation System Changes, “Chapter 14 Road Value Pricing,” 2003
    • FHWA Report No. FHWA-OP-03-009, “A Guide for HOT Lane Development,” 2003
    • FHWA Report No. FHWA-HOP-05-037, “Managed Lanes: A Cross-Cutting Study,” 2004
    • Transport for London’s “Central London Congestion Charging Impacts Monitoring: 4th Annual Report,” 2006
    • Victoria Policy Institute report, “London Congestion Pricing,” by Todd Litman, 2006
    • “Road pricing” section of the Victoria Policy Institute’s TDM Encyclopedia website
• Advanced Parking Systems
  • Advanced parking systems help drivers find or reserve parking, automatically store cars within the facility, enable wireless and/or electronic payment, and/or convey real-time information regarding the status of a lot or metered space. Such systems are thought to decrease congestion both on local streets, by reducing the need to circle in search of parking, and within parking facilities, by helping motorists find and pay for parking more quickly. In some situations, real-time information about downstream parking sites can also help motorists make more informed mode-choice or route decisions.
    Impact on Congestion — Traffic flow impacts in a downtown area with real-time parking availability signs included 9 percent reduction in travel time, 10 percent reduction in vehicle delay, and intersection volume increased by 15 percent. ²² For participants in a pilot study of a high-tech park-and-ride facility, VMT and travel time were reduced, and transit mode share increased. ²³ In a survey of National Park visitors, 44 percent of respondents reported that real-time parking information helped them decide to ride the bus. ²⁴
    Financial Cost — According to one estimate, advanced parking systems cost $250 to $800 per space, depending on the type of information provided, system complexity, required signage, and the availability of communications and power supplies. ²⁵ An automated monitoring system is estimated at $19,000 to $41,000, billing software at $10,000 to $15,000, and electronic tag readers for electronic payment at $2,000 to $4,000 each. ²⁶
    Additional Resources
    FHWA Report No. FHWA-JPO-07-011, “Advanced Parking Management Systems: A Cross-Cutting Study,” 2007
    “Smart Parking Management to Boost Transit, Ease Congestion: Oakland, California, Field Test Shows Promise,” by Susan A. Shaheen and Caroline Rodier, TR News 251, 2007
    Parking
    Advanced Parking section of the ITS Benefits, Costs, and Lessons Learned websites
• Speed Harmonization
  • Speed harmonization to dynamically and automatically reduces speed limits approaching areas of congestion, accidents, or special events. The intended benefit is to maintain flow and reduce risk of collisions.
    Impact on Congestion — Speed harmonization results in smoother traffic flow and reduced crash rates. Depending on the extent of the system, benefits range from 3 to 50 percent reduction in incidents, 3 to 10 percent increase in throughput, and 3 to 22 percent increase overall in capacity. ²⁷
    Financial Cost — While speed harmonization has not been used in the United States, dynamic speed limits adjusted to accommodate weather conditions may have similar capital requirements, such as the system implemented along the Snoqualmie Pass corridor at a cost of $5 million for design and implementation.28 See also per unit costs described in the “Dynamic messaging” section of this report.
    Additional Resources
    • FHWA Report No. FHWA-PL-07-012, “Active Traffic Management: The Next Step in Congestion Management,” 2007
    • “Variable Speed Limits” section of the ITS Benefits, Costs, and Lessons Learned databases
    • ATM Feasiblity Study
• Dynamic Messaging
  • Dynamic messaging uses changeable message signs to warn motorists of downstream queues, directs through-traffic to alternate lanes, provides travel time estimates, provides alternate route information, or provides information about special events, weather conditions, or other incidents. This particularly refers to messaging that is highly responsive to current conditions, such as using automated detection systems and remote surveillance. Such systems are thought to mitigate congestion by diverting traffic to alternate routes and by helping to prevent new incidents by diminishing speed differentials and collisions related to queuing or other temporary conditions.
    Impact on Congestion — Dynamic messaging has been found to significantly reduce non-recurrent congestion. For instance, a queue warning system on Swedish highways reduced vehicle delay 85 percent, increased vehicle speeds during incidents 300 percent, and resulted in overall higher average speeds with less variation during peak and congested times. ²⁹ Real-time incident detection and warning along an accident-prone Japanese facility reduced the rate of secondary crashes by 50 percent. ³⁰ During incidents or congestion, up to 40 percent of travelers have been found to alter their route in response to dynamic messaging on various facilities. ³¹
    Financial Cost — Varies greatly with the extent of the system. Capital costs associated with each dynamic message sign and tower are $74,000 to $245,000 each, plus $10,000 to $16,000 per mile of wireline to each sign. Sensors and cameras for remote monitoring or automated detection contribute additional costs, as do maintenance and operation of all equipment. ³²
    Additional Resources
    • FHWA Report No. FHWA-PL-07-012, “Active Traffic Management: The Next Step in Congestion Management,” 2007
    • U.S. DOT, ITS Joint Program Office, “Intelligent Transportation Systems for Traffic Incident Management” leaflet, Publication No. FHWA-JPO-07-001, 2007
    • European Commission Report, “Queue Warning System on the E6, Gothenburg, Sweden,” 2007 available from the European Commission Evaluation Expert Group online library
    • “Dynamic Message Signs” section of the ITS Benefits, Costs, and Lessons Learned websites
• Incident Management Systems
  • Incident management systems are technical and procedural systems that assist in the efficient handling of incidents, such as emergency response, highway service patrol, highway advisory radio, and incident detection.
    Impact on Congestion — Incident management systems have been shown to significantly reduce nonrecurring congestion, improving incident clearance time by up to 69 percent and reducing the rate of secondary crashes by up to 50 percent. ³³
    Financial Cost — Highway service patrol programs around the country report operating budgets between $1 million and over $20 million annually, calculated as $55 per hour in one state. ³⁴ Other components of an incident management system imposing both capital and operating costs might include sensors, cameras, dynamic messaging signs, wireline communications, radio communications, and traffic or emergency management centers.
    Additional Resources
    • Traffic Incident Management section of the ITS/Operation Resource Guide 2007 website
    • “Incident management systems” and “Emergency management systems” sections of the ITS Benefits, Costs, and Lessons Learned websites
    • Traffic Incident Management Program section of the FHWA’s Office of Operations website
    • National Traffic Incident Management Coalition (NTIMC) website
    • FHWA Report No. FHWA-JPO-07-001, “Intelligent Transportation Systems for Traffic Incident Management: Deployment Benefits and Lessons Learned,” 2007
    • FHWA Report No. FHWA-HOP-06-004, “Simplified Guide to the Incident Command System for Transportation Professionals,” 2006
• Special Events and Work-Zone Planning
  • These are procedures and systems for managing the impact on traffic of construction projects, disasters, or irregular events drawing large crowds.
    Financial Cost — Successful planning can significantly reduce nonrecurring congestion associated with special events. For instance, an automated work zone information system reduced congestion delay by 50 percent on a California interstate. ³⁵
    Additional Resources
    • Planned Special Events Traffic Management Section of the FHWA Office of Operations website
    • Traffic Incident Management section of the ITS/Operation Resource Guide 2007 website
    • FHWA Report No. FHWA-OP-04-010, “Managing Travel for Planned Special Events Handbook,” 2003
    • U.S. DOT, ITS Joint Program Office, “Intelligent Transportation Systems for Work Zones” leaflet, Publication No. FHWA-JPO-07-003, 2007
    • FHWA Report No. FHWA-OP-05-017, “Managing Travel for Planned Special Events: First National Conference Proceedings,” 2005

Alternative Mode Support Strategies

• Public Education and Promotion
  • A lack of understanding of available transportation options has been identified as a major barrier to alternative mode use. Marketing and public education programs can help overcome that barrier, effectively making the use of those alternative modes more convenient.
    Impact on Congestion — While the impact of mass marketing campaigns on ridership (and in turn VMT and congestion) is inconclusive, targeted marketing to specific groups has proven more successful, with up to 50 percent increases in riding as a result. ³⁶ In addition, individualized marketing techniques such as in Perth and Brisbaine have resulted in 14 percent reduction in vehicle use, 17 percent increase in transit use, and 35 percent increase in walking, among 15,300 households participating in one effort. ³⁷ One report suggests that the most important determinants of marketing success are research on travel needs and the ability to point to services that accommodate those needs, noting that “the best information and marketing programs cannot save a bad product or no product at all,” but can play an important role in helping good transportation options “promote themselves.” ³⁸
    Financial Cost — “With the exception of an elaborate advertising campaign, public education can typically be provided for minimal costs. Additionally, because of the public nature of the advertising, free media time or space can often be obtained.” ³⁹
    Additional Resources
    • “TDM Marketing” section of Victoria Policy Institute’s TDM Encyclopedia website
• Shuttle Services
  • Shuttle services are a subset of public transportation using vans, shuttles, or small buses to fill gaps in the transportation system, often serving very small or particular market segments. They may follow either fixed or variable routes, and may operate either according to a fixed schedule or only by demand, including demand-response paratransit, circulator shuttles, jitneys, night shuttles on college campuses, airport shuttles, and business-specific shuttles (such as to hotels or corporate campuses).
    Impact on Congestion
    While shuttle services are likely to have a negligible impact on overall congestion, they may enable some motorists to replace or shorten vehicle trips with shuttle and transit trips, thus complementing other strategies that may work together to reduce VMT and vehicle use. In addition, shuttle users themselves may encounter less congestion delay if shuttle vehicles are able to utilize HOV facilities or signal preemption along their routes. ⁴⁰
    Financial Cost — Shuttle services inherently serve relatively low numbers of passengers, and therefore the cost per passenger can sometimes be high. One study finds that circulators and shuttles in the United States operate at a cost of between $1 to $7 per passenger, ⁴¹ although other types of services operate for profit, such as airport shuttles in the U.S. and jitney services in many places outside the U.S.
    Additional Resources
    • TCRP Report 55, “Guidelines for Enhancing Suburban Mobility Using Public Transportation,” 1999
    • TCRP Report 95, Traveler Response to Transportation System Changes, “Chapter 6 ? Demand-Responsive/ADA,” 2005
    • “Shuttle Services” section on the Victoria Policy Institute’s TDM Encyclopedia website
    • Victoria Policy Institute’s report, “Evaluating Public Transit Benefits and Costs: Best Practices Guidebook,” by Todd Litman, 2006
• Ridesharing Programs
  • Programs that facilitate carpool formation, including ride-matching services and vanpool programs. While ride-matching usually implies the use of passenger-owned vehicles, vanpooling may utilize van fleets owned by an implementing agency or private company, differing from shuttle services in their reliance on passengers to act as volunteer drivers. Other types of strategies discussed elsewhere in this report that potentially promote ridesharing include HOV lanes, parking management, guaranteed ride home policies, and other employer-based programs.
    Impact on Congestion
    Rideshare programs are most effective when combined with financial incentives such as parking cash-out or subsidies, thought to reduce vehicle trips to particular sites by 5 to 20 percent or up to 30 percent with sufficient incentives. ⁴² While incentives may draw carpool and vanpool riders from transit undermining the goal, studies indicate a significant share formerly drove alone, estimated to at 50 percent among King County vanpoolers. One study estimated that vanpoolers in Massachusetts had reduced their VMT 76 percent. ⁴³ Thus, although the impact of isolated rideshare programs on regional congestion may be negligible in most areas, such programs reduce VMT and complement other strategies designed to reduce peak-hour vehicle use. In addition rideshare participants may themselves experience less congestion delay if they are able to utilize HOV lanes and priority parking.
    Financial Cost
    Ride-matching programs primarily incur administrative costs, which vary depending on the sophistication of the matching system, ranging from a notice board or hand-referral system on the low end to a computerized matching system that takes into account each commuter’s origin, destination, schedule, and special needs. Ride-matching programs may also be tied to a marketing campaign, which may add significant costs. Some vanpool programs operate for profit, but many others are implemented by public agencies that partially subsidize passengers’ travel. One study found that annual operating costs for public agency vanpool programs were $15,000 to $16,750 per vehicle, with subsidies provided at a rate of between $0 (assisting with start up costs only) to $400 per passenger annually. ⁴⁴ In general, vanpool programs usually recover a much larger share of operating costs through rider fees than public transit.
    Additional Resources
    • TCRP Report 55, “Guidelines for Enhancing Suburban Mobility Using Public Transportation,” 1999
    • TCRP Report 95, Traveler Response to Transportation System Changes, “Chapter 3 ? Park-and-Ride/Pool”
    • “Chapter 5 ? Vanpools and Buspools”
    • “Successful Risk Management for Rideshare and Carpool-Matching Programs,” Legal Research Digest 2(September), 1994
    • CUTR Transportation Research Study, “Price Elasticity of Rideshare: Commuter Fringe Benefits for Vanpools,” by Fancis Wambalaba, Sisinnio Concas, and Marlo Chavarria, 2004
    • Puget Sound’s “Vanpool Market Action Plan,” 2003
    • “Ridesharing” section of the Victoria Policy Institute’s TDM Encyclopedia website
    • Section on ridematching systems and software on CUTR website
    • Rideshare website for King County and beyond
    • Information from WSDOT on vanpooling in Washington state

Other Demand Management

• Traveler Information, Public Relations, and Marketing
  • Traveler information can be used to notify travelers of transportation options, to promote particular options, and to tailor options to traveler needs and preferences. All of these types of traveler information can be used to help travelers avoid congested conditions and to opt for alternatives that contribute less to congestion. Information may be disseminated to the public via broadcast media, written materials, signage, websites, hotlines, handheld devices, or in-vehicle devices. Marketing activities may additionally include surveys, user feedback, and market-based planning to better tailor transportation alternatives to users’ needs and preferences.
    Impact on Congestion — Information about traffic conditions and special events has been shown to influence travel choices and help users avoid and reduce congestion. For instance, one study found that about half of 511 users changed their travel plans as a result of information learned. An automated work zone information system resulted in a 50-percent reduction in peak-period delay on one California interstate. ⁵⁵ Transit route, fare, and schedule information are essential aspects of mode choice decisions and their distribution may influence ridership. For instance, up to 20 percent of transit riders accessed transit websites in 2001. ⁵⁶
    Financial Cost — The cost of providing traveler information varies greatly with the range of types of service or campaign. Design, implementation, and one year of operations for a statewide 511 system costs about $2.5 million for statewide systems, according to one review. ⁵⁷ Several transit agencies reported spending about $10,000 on targeted marketing campaigns, up to $2,000 on mass marketing campaigns. ⁵⁸
    Additional Resources
    • NCHRP Report 95, Traveler Response to Transportation System Changes, “Chapter 11 – Transit Information and Promotion,” 2003
    • “Traveler Information” section of the ITS/Operations Resource Guide 2007 website
    • “TDM Marketing” section of Victoria Policy Institute’s TDM Encyclopedia website
    • “Traveler information” section of the ITS Benefits Database website
    • U.S. DOT, ITS Joint Program Office, “Intelligent Transportation Systems for Traveler Information” leaflet, Publication No. FHWA-JPO-07-002, January 2007
• Parking Management and Pricing
  • These are strategies that reduce the availability of free parking places, especially in locations served by congested routes. Parking management may be in the form of area-wide policies or may be specific to particular sites. Policies might include lowering the maximum (or reducing the minimum) number of spaces permitted (or required) per employee, household, or 1,000 square-feet of office space; increasing the share of spaces reserved for HOV vehicles; introducing or raising parking fees; providing cash-out options for employees not utilizing subsidized parking spaces; and expanding parking at transit stations and park-and-ride lots.
    Impact on Congestion — Because parking is a necessary component of most vehicle use, parking management has been shown to have a dramatic effect on travel choices, increasing transit use and vehicle occupancy. ⁵⁹ For instance, although the SOV share for most suburban worksites in the Seattle area is about 80 percent, some Bellevue employers achieved shares as low as 26 percent, through a combination of on-site and citywide parking management. ⁶⁰ Similarly, a study of eight firms that began offering employee cash-out programs in Los Angeles showed that the program resulted in an increase in carpooling (64 percent), transit use (50 percent), and walking or biking (39 percent), and a decrease in driving alone (17 percent), resulting in an overall 12 percent decline in commute VMT, on average, and up to a 24 percent decline at worksites in the downtown area. ⁶¹ However, such policies have generally not been implemented widely enough to document significant reductions in regional VMT or congestion.
    Financial Cost — Since the provision of parking spaces is costly, reducing their number and/or increasing parking fees are a net financial gain. Implementing pricing mechanisms on previously free parking imposes both capital and operating costs associated with the pricing mechanism, in addition to the cost of enforcing parking regulation, although all of these would be covered by parking-fee revenues.
    Additional Resources
    • TCRP Report 95, Traveler Response to Transportation System Changes, “Chapter 13 – Parking Pricing and Fees,” 2005
    • “Chapter 18 – Parking Management and Supply,” 2003
    • “Parking management”
    • “Parking pricing” sections of Victoria Policy Institute’s TDM Encyclopedia website
    • Special issue of the journal Transport Policy devoted to issues related to parking, Volume 13 number 6, November 2006
    • High Cost of Free Parking, by Donald Shoup (APA Planners Press), 2005
    • A Powerpoint presentation by Shoup based on the book’s contents
    • Victoria Policy Institute Report, “Parking Management: Strategies, Evaluation and Planning,” by Todd Litman, 2007
• Telecommuting Programs
  • Telecommuting programs enable employees to telecommute or telework, that is, to use telecommunications (phone, Internet, video-conferencing, remote desktop, and others) to substitute for physical travel to a worksite. Such programs may include employer policies enabling employees to work at home, the establishment of telework centers to serve as alternate worksites for telecommuters, or regional campaigns to promote telecommuting, such as through education, technical assistance, and financial incentives such as tradable credits.
    Impact on Congestion — Telecommuting has the potential to reduce peak-hour VMT substantially by doing away with the commute trip for an estimated 50 percent of the U.S. workforce whose duties are theoretically compatible with at least part-time telecommuting. ⁶² However, few employees actually do telecommute, and among those that do, there is wide variation in how often and in what way, making VMT and congestion impacts variable and difficult to estimate. For instance, employees telecommuting only for part of the day would not reduce their VMT, but may shift one half of their commutes to an off-peak time, and therefore decreasing their contributions to congestion. In addition, there is evidence that telecommuting enables some employees to live farther from work, that employees working at home may increase other trip-making during the day, and that the growth in telecommunications in general has stimulated more and not less travel overall, all of which may undermine some of the benefits of telecommuting. However, research suggests that nationwide telecommuting has reduced VMT by 0 to 2 percent annually, or by about 30 miles per telecommute day per employee. ⁶³ While the Impact on congestion is likely negligible, these results suggest that telecommuters reduce their personal exposure to congestion and that larger effects may be observed if more employees tried it.
    Financial Cost — Telecommuting costs may be minimal if enabled by existing infrastructure, such as phones and Internet connections, likely resulting in overall savings for the employee. ⁶⁴ Programs promoting telecommuting may have variable costs. A Telework Demonstration Project conducted by the Metropolitan Washington Council of Governments cost $397,600, including the provision of consulting services to help employers start or expand telecommute programs and analysis of the results. ⁶⁵ In general, telecommuting programs are thought to require minimal investment relative to the payoff in VMT reductions. ⁶⁶
    Additional Resources
    • CMAQ and Telecommute Programs section of the FHWA website
    • “Telework” section of Victoria Policy Institute’s TDM Encyclopedia website
    • “Does Telecommuting Reduce Vehicle-miles Traveled? An Aggregate Time Series Analysis for the U.S.”, by Sangho Choo, Patricia L. Mokhtarian, and Ilan Salomon. Transportation 32(1), 2005, 37?64
    • JALA International’s online cost-benefit tool for estimating personal costs or savings associated with telecommuting
    • “Work from home” section of WSDOT Commute and Travel Info website
• Flexible Work Schedules
  • Flexible work schedules allow flextime, a compressed work week (such as 4/40 or 9/80), or staggered shifts that enable employees to reduce peak-hour trip-making.
    Impact on Congestion Commute VMT has been shown to diminish among employees on flexible work schedules. For instance, one study finds that a 4/40 work week in Los Angeles enabled a reduction of 46 miles per week per employee, on average. ⁶⁷ One researcher estimates that if combined with telecommuting opportunities, peak-hour vehicle trips can diminish 20 to 50 percent. ⁶⁸ However, the overall Impact on congestion has been negligible, since such a small share of the work force uses flexible schedules. There may be more of an effect observed if more employees were able to adopt flexible schedules. Furthermore, those who do adopt flexible schedules are able to reduce their personal exposure to congestion.
    Financial Cost There are few costs associated with voluntary flexible-schedule policies adopted by employers, perhaps limited to some increase in some administrative effort.
    Additional Resources
    • “Alternative Work Schedules” section of Victoria Policy Institute’s TDM Encyclopedia website
    • “Compressed Work Week” section of the WSDOT Commute and Travel Info website
    • EPA TRAQ Technical Overview, Report No. EPA420-S-98-014, “Transportation Control Measures: Work Schedule Changes,” 1998
• Distance-Based Insurance
  • Also known as pay-as-you-drive (PAYD) insurance and other names, these are automobile insurance policies whose premiums are determined by the number of miles driven during the policy term. The primary appeal of such programs is economic efficiency, so that prices better reflect costs. They also are expected to offer overall savings to consumers, to be more affordable and fair, to reduce rates of accidents and uninsured drivers, and to reduce overall vehicle travel by providing consumers incentives to drive less. Although it does not target peak-hour use specifically, PAYD insurance could help reduce congestion by helping decrease vehicle use in general.
    Impact on Congestion Distanced-based insurance has not been implemented on a wide enough scale to evaluate its impacts. However, modeling exercises indicate that adoption by all drivers in a region could reduce congestion delays by 10 to 25 percent. ⁶⁹
    Financial Cost The cost to insurers of transitioning to a new pricing system is thought to be covered by overall cost savings under the new scheme. Savings passed on to consumers are estimated at $50 to $100 per year for the average motorist.V70^
    Additional Resources
    • See “Pay-As-You-Drive Vehicle Insurance” section of the Victoria Policy Institute’s TDM Encyclopedia website
    • Press release on pilot mileage-based insurance program in Washington State

More Information

• Recommended Resources
  • ITS Costs and Benefits Databases
    Hosted by the ITS Joint Program Office of the USDOT (last update in May 2007), this set of databases provides assembles findings from projects throughout the U.S. and internationally on the costs, benefits, and lessons learned from ITS deployment projects.
    Online Version of the ITS/Operations Resource Guide
    Hosted by the ITS Joint Program Office of the USDOT (last update in 2007), this guide provides links to reports, documents, websites, and other resources on a wide range of topics relating to ITS and operations.
    Online TDM Encyclopedia
    Hosted by the Victoria Transport Policy Institute (last update in September 2007), this website provides detailed information about a variety of demand management strategies, cross-indexed by the types of goals they help achieve and by implementing stakeholder group. Entries include a discussion of specific estimates of benefits and costs, travel and equity impacts, evaluation metrics, barriers to implementation, case studies, and resources for more information.
    Benefit-Cost Analysis of Bicycle Facilities website
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    Transport Canada TDM Database
    Hosted by Transport Canada, this resource serves as a clearinghouse for research and results relating to implemented TDM strategies throughout North America.
    TCRP Report 95, Traveler Response to Transportation System Changes
    Published by the Transit Research Cooperative Program, this document includes 19 chapters, each acting as a stand-alone report on one of a variety of different management areas relating to highways, transit, nonmotorized modes, pricing, and land use. Each chapter was published between 2003 and 2005, providing a detailed overview of the state of the practice as well as a comprehensive view of research to date in each subject area.
    European Commission TEMPO Evaluation Expert Group Online Library
    Hosted by the European Commission’s TEMPO Evaluation Group, this website provides an archive of reports on the results for their ITS implementation projects throughout Europe.