Civil Engineering Reference
In-Depth Information
A comprehensive analysis of traveler response to HOV facilities is provided in
Chap. 2 of TRCP Report 95 [
19
]. Some of the salient
findings from this chapter are
summarized as follows:
1. The attractiveness of HOV facilities depends upon the amount of time that users
save, the trip time reliability afforded, the type and frequency of bus service,
facility location and orientation, HOV eligibility requirements, years in service,
availability of park-and-ride facilities. Corridor congestion levels (freeway lanes
and parallel arterials), the size and con
guration of urban area population and
major attraction centers are critical determinants of use.
2. Most HOV facilities carry more people per lane than do the adjacent general
purpose lanes in the peak hour
and sometimes in the entire peak period.
Illustrative examples of AM peak-hour vehicle and person volumes on HOV
facilities include:
—
About 500
600 buses carrying 23,000 passengers on the NJ Route 495 bus-
only contra-
-
fl
ow lane approaching the Lincoln Tunnel to New York City
1,200 vehicles (including 22 buses) carrying 3,600 people (including 1,100)
bus passengers) on the exclusive Northwest HOV lane in Houston
1,200 vehicles (including 64 buses) and 5,600 people (including 2,600 bus
passengers) on the I-5 North concurrent
fl
flow lanes in Seattle, and
1,300 carpools and vanpools with 3,000 occupants on the concurrent HOV
lanes of the California Route 91 in Los Angeles County
3. Radial facilities with higher bus volumes generally have serve the highest
number of travelers in the HOV lanes.
4. Travel time savings and reliability improvements result from short queue bypass
HOV lanes as well as longer facilities used to bypass traf
c bottlenecks.
Table
17.5
gives examples of peak hour travel time savings reported for various
HOV facilities.
Time savings vary from day to day, and they might be much less in the shoulders
of the peak hours than in the time span of peak congestion in the general purpose
lanes. The travel time savings range up to almost 40 min: (a) where HOV lanes
function as queue bypasses at toll stations and other bottlenecks such as water
crossings, they range from about 6
20 min per mile on HOV facilities; (b) longer
HOV facilities along freeways provide savings of up to 1.6 min per mile; (c) HOV
lanes on arterial streets typically save about 0.5 min per mile.
Contributing factors to successful HOV lanes generally include:
-
Metro area population of at least 1.5 million people
HOV lanes serving major employment centers with more than 100,000
jobs
—
preferably a CBD
Geographic barriers that concentrate development and constrict travel
Potential for at least 25 buses per hour using the NOV facility
