This paper presents the results of some studies of the extensive use of High Occupancy Vehicle (HOV) lanes on area freeways in the Milwaukee area in Wisconsin, USA. This use focuses on increasing the person-movement capacity of the roadway facility, which represents a potential solution to traffic congestion and air quality problems in the area. Before-and-after studies of HOV lanes in other cities indicate that HOV lanes have a positive effect on car occupancy rate and the number of vehicle miles travelled, so that vehicle emissions decreased. To decrease congestion and harmful emissions, vehicle volumes on the freeways must decrease. The following types of HOV lane can be implemented in the Milwaukee area: (1) exclusive HOV facility, with separate right of way; (2) exclusive HOV facility, with freeway right of way; and (3) concurrent flow lane. After the implementation of HOV lanes, the respective numbers of vehicle miles travelled on the freeway and in the area by 2005 are expected to be about 5% and 2% lower. The resulting 2% reduction in emissions by 2005 is only a tiny proportion of the 45% Clean Air Act reduction target, so that other, drastic, changes in transport will also be needed.
Samenvatting