Automating Urban Freeways
Sustainable Transportation Energy Pathways (STEPS), Urban Land Use and Transportation Center
Johnston, Robert A., Daniel Sperling, Paul P. Craig, Jay R. Lund (1988) Automating Urban Freeways. ITS Review 11 (4), 4 - 8
Urban residents are becoming frustrated and angry as traffic congestion continues to worsen. Indeed, surveys show that the public often perceives transportation as the number one urban problem—surpassing crime, housing, education, and drugs. Yet no compelling solution has emerged. For that reason, interest in the concept of automated control of motor vehicles on highways has gained renewed attention. Highway automation is an appealing concept because it promises increased capacity without having to build new highways. It is a technical fix that allows continued dependence on automobiles and avoids conflict with local communities opposed to new freeways. Automation promises reduced accidents, increased roadway capacity, and faster trips and reduced stress for the driver. Automated technology would lessen dependence on the slow, imprecise, and erratic reactions of drivers (including those under the influence of alcohol and drugs), and would provide routing and traffic flow information to enable automatic selection of the fastest route. Drivers would experience less stress, shorter travel times, and eventually would be able to use their time in vehicles for purposes other than driving. But will all these wonderful benefits ever be realized? As a preliminary exploration of the concept and promise of highway automation, we sketch a likely implementation path for the advanced technologies and explore some of the important policy issues associated with this implementation path. We focus on urban areas because they experience the worst problems, and on freeways because they carry a disproportionately large share of the traffic. First, as background, note that highway automation encompasses three sets of technologies: navigational information and controls so that vehicles follow optimal routes from origin to destination; lateral control of vehicles within lanes; and longitudinal control between sequential vehicles. Increased capacity would result from shortened headway distances between vehicles, smoother and more efficiently routed traffic flows and possibly reduced lane widths.