Understanding the relative attractiveness of alternatives to driving is vitally important toward lowering driving rates and, by extension, vehicle miles travelled (VMT), traffic congestion, greenhouse gas (GHG) emissions, etc. The relative effectiveness of automobile alternatives (i.e., buses, bicycling, and walking) depends on how well streets are designed to work for these respective modes in terms of safety, comfort and cost, which can sometimes pit their relative effectiveness against each other. For example, a street network that works well for high-speed vehicle traffic may work well for buses, but not for bicyclists and pedestrians. Until now, little research has been done looking at the quality of the street environment in terms of how it functions for the relative attractiveness of sustainable human-powered (bicyclists and pedestrian) and vehicle transport (bus transit). Building on previous research and the development of an innovative measure of traffic stress, this study reveals the often competing characteristics of safety and comfort against the speed and reliability that can drive the attractiveness of these modes. In this report, the level of traffic stress (LTS) criteria from MTI report 10051 was used to determine how the streets in our study areas functioned for these auto-alternative modes. Specifically, the LTS criteria used for this study include vehicle speeds, number of lanes, presence of parking, presence of bike lanes, and intersection type (whether signalised or unsignalised). The quality and extent of the transit service area was measured using a total travel time metric over the LTS network. The model developed in this study was applied to two transit routes in Oakland, California, and Denver, Colorado. The key research findings and recommendations are as follows: • Higher LTS levels (LTS 3 and 4) networks around transit routes are uncomfortable and unattractive for bicycling and walking–essentially, the traffic becomes a stressful barrier to non-motorized travel–thereby limiting the effective catchment area of the transit service. The recommendations from MTI Report 10052 to make sure connectivity is maintained through the provision of safe crossings to destinations/ attractors such as transit stations is again re-emphasized. • For streets and networks with LTS level 2 or below, bus travel times are comparable to bike riding times to the point that they limit the effective attractiveness of bus transit service for bicyclists who use a bicycle/bus mode. This study suggests that the effective bus transit service catchment area can be constrained to within a one-mile network distance around the transit stops. • Paradoxically, changes in network LTS can shift the relative attractiveness of once complementary mode pairings (e.g., a bicycle/bus-transit mode choice) toward becoming directly competitive and substitutable with each other (e.g., a bicycle/ transit versus a bicycle-only mode choice). For instance, at lower levels of traffic stress (LTS 1 or 2) the choice between a bicycling/bus transit and bicycle-only modes become equally attractive and substitutable, especially if you are a bicyclist outside the one-mile range of a regular service bus stop. In these cases, travel time between a bicycle/bus-transit trip and bicycling-only become more alike, and therefore the choice between the modes becomes interchangeable. Bicycling all the way to the destination becomes more attractive, especially considering transfer penalty, availability of parking, on-board accommodation, and cost, as well as the bicyclist’s independence and self-determination regarding the characteristics of their trip (on-demand, route choice, trip chaining, opportunity to exercise, etc.). • Improving transit mobility and the comfort and encouragement of pedestrians and bicyclists to access a larger service area than traditionally attributed to transit produces the highest livability and increases alternatives for the traveller. Therefore, we recommend that urban areas design and plan for LTS 2 levels, accompanied by enhancements to help transit operate more efficiently in conjunction with pedestrian and bicyclist comfort and safety improvements. Some measures to thoughtfully consider include transit-only lanes, transit priority lanes at the intersections, transit-stop bulb-outs, and integrated networks of pedestrian and bicycle routes throughout the metropolitan area. (Author/publisher)
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