NEW TOLL ROAD VS. TOLL MANAGED LANES ON EXISTING MOTOR- WAYS: ALTERNATIVES AND IMPACTS IN METRO WASHINGTON, DC

The design of managed toll lane networks raises a number of important issues with major implications for the environment, transportation system performance, traffic congestion, and transportation finance. These are discussed in the context of the metropolitan Washington, DC area, where a regional task force has defined goals for the managed toll lane network plan and where corridor-level analyses have been completed or are underway. Debate is growing over how toll lanes might be designed and operated. Will tolls solely pay for new highway lanes or help finance expanded public transport services? Will such lanes be optimized to support Bus Rapid Transit (BRT) with efficient access to adjacent centers and public transport lines or will bus use of toll lanes be an afterthought? Will toll lane BRT stations facilitate walking and bicycling access and transit-oriented development? What are the implications for transportation costs, revenues, and environmental performance? This paper reviews these issues in the Washington region and summarizes findings from several corridor studies. A study by the authors compares a proposed $2 billion Intercounty Connector tolled outer beltway in suburban Maryland with less costly investment and management strategies serving the area, with project concepts drawn from official planning studies. Using official regional travel and emission models, the study analyzes and compares changes in travel time, mode choice, traffic volume, emissions, revenues, and other attributes. A new outer beltway with express bus service is less effective in relieving traffic than connecting the end-points of the proposed outer beltway with High Occupancy Toll (HOT) lanes converted from general purpose lanes on existing freeways, supporting new BRT services, but this HOT conversion leaves local roads more congested. Better performance at higher cost comes by adding a new toll managed lane to existing motorways while converting some existing general purpose motorway lanes to toll managed lanes, combined with new BRT services. Yet these alternatives are surpassed in most respects by the option of expanded rail and bus public transportation in the corridor and redirected new job and housing growth to areas with a high level of public transportation access with better balancing of jobs and housing in subareas. The best performance generally results from converting some existing motorway lanes to HOT/BRT lanes in combination with the public transportation oriented investment and land use scenario.