TIME IN MOTION: ACCELERATION, MERGING, & ROUTE DIVERGENCE
Acceleration, deceleration, and door operation time approaching or leaving a stop can add 15–30 or more seconds per stop. Consolidating from stops to stations and introducing rapid services can dramatically reduce this time expenditure.
For buses in particular, merging into or re-entering the flow of general traffic after a conventional curbside pull-out stop is a perennial source of delay. Reduce this delay by providing in-lane stops and stop-related signal treatments (see Signals & Operations, and Stop Placement & Intersection Configuration), or by enforcing a yield-to-bus law.
Circuitous routes and turns can be time consuming for transit operators and confusing for passengers, often adding significantly to travel time. Keeping transit lines simple and direct serves to minimize this delay, improving transit travel times. While this may increase the time spent walking to a stop, it can benefit overall trip times. Evaluate any changes based on a walking network model and transit travel times.
PASSENGER ACCESS & WAIT TIME
In addition to on-board transit time, a passenger’s trip time also includes time spent walking to a stop, waiting for transit to arrive, making any transfers, and accessing a destination. Since passengers place 2.5 times more value on a shorter wait than on a shorter amount of time spent in motion or a shorter walk to transit, a small improvement in wait time can provide a larger benefit to passengers and a greater boost to ridership than a similar improvement in speed.
Table of “Deterrent Effect of Various Kinds of Travel Time,” Exhibit 4-5. “Ch. 4: Quality of Service Concepts.” TCQSM, 3rd ed. (2013).
Reliability affects how passengers perceive wait times. If wait time and travel time vary significantly, or are routinely much longer than the scheduled time, passengers build this time into their trips, and transit becomes less useful for them.
Transit and street design can make wait time valuable to passengers by providing comfortable waiting areas at stops (see Stations & Stops), by providing real-time information to reduce start-of-trip wait times, and by reducing the time needed for transfers through network design (see Transit System Strategies). Quality urban street design can make walking to a transit stop a positive feature of transit trips.
UNLOCKING OPERATIONAL EFFICIENCIES
Addressing the main sources of transit delay has two related benefits. It shortens door-to-door time for a passenger trip, improving the competitiveness of transit. It also reduces the time and cost of each transit vehicle’s run, enabling a transit agency to provide more frequent service to each stop with the same number of vehicles and drivers. In this context a small travel time savings is a large cost savings.
Buses in mixed traffic are susceptible to a downward service spiral, in which increased congestion—exacerbated over the long term by designing streets primarily to accommodate private motor vehicles—results in lower ridership and revenue, resulting in service cuts and lower ridership and revenue.
This cycle can be reversed by improving on-street transit travel times. Shorter travel time allows transit operators to run more frequent service, with more runs per hour using the same number of vehicles and drivers. Greater frequency and shorter trip time yields higher ridership, raising revenue and permitting still greater service frequency.
For detailed information and analysis of transit delay, see the Transit Capacity and Quality of Service Manual, 3rd Edition.