About this Data
1. Access to Frequent Transit Versus Any Transit. This data is from the AllTransit website, and is calculated from GTFS data for the pre-BaltimoreLink system. The "frequent transit" measure refers to transit with 15 minute headways or shorter during rush hour within 1/2 a mile (AllTransit also measures frequent transit at other time intervals). MTA has reported that access to frequent transit has increased by over 30% for BaltimoreLINK, however they have not revealed the baseline for calculating that percentage increase, or the total number of persons who now have access to frequent transit. See more detail below about the different approaches to calculating frequent transit.
2. 24-hour Service Frequency, CityLink Blue (Weekday). This data is from MTA's schedule for the CityLink blue, and provides distribution of headways. throughout the 24-hour period during which the CityLink blue operates.
What We Know
Why Frequency Matters
As transit consultant Jarrett Walker would put it, "Frequency is Freedom." Frequency affects wait time and ensures that transfers between lines are timely. When service is frequent, riders can simply show up to their bus stop without having to worry so much about planning their trip using a schedule. The "freedom" yielded by this frequency is the freedom to simply move on one's own schedule when using frequent service, much as the owner of a private car can simply walk to wherever their vehicle is parked whenever they are ready to begin a new trip.
Because of this, some transit agencies focus on headway management rather than the use of a traditional schedule for frequent services. The MTA now focuses on headway management for its frequent CityLink services, and prior to that, the Charm City Circulator piloted service in Baltimore City that promised 10-minute headways and accurate real-time information in place of a traditional schedule.
How MTA Defines Frequency
The MTA has reportedly defined frequency as service between the hours of 7AM and 7PM that maintains headways of 15 minutes or less. MTA's CityLink buses and some LocalLinks offer this service, typically with 10 or 15 minute frequencies during AM and PM peak times, and 15 minute frequencies during the midday. Generally, that means frequent service is not provided after 7PM most eveninings, or before 7AM most mornings, nor is frequent service provided on most routes during the weekend.
There is not a standard definition of frequent transit service. Jarrett Walker has suggested that for cities outside of the largest major American cities, a "15-15-7" standard is acceptable, or 15 minute or better service, 15 hours a day, 7 days a week.
What We Need
Analysis of How Proposed Service Changes Affect Access to Frequent Service
When MTA releases its triennial service changes there can be a big impact on frequent access. Since jobs access and access to frequent transit were two of the top metrics MTA used to plan and promote the BaltimoreLINK system, the public should know how proposed scheduled changes are affecting the numbers that were provided to stakeholders prior to launch.
A Way to Compare Scheduled and Real-World Frequencies
Frequency and reliability are closely related, especially when it comes to riders' wait time. A late bus is also a bus that misses its advertised headway (and for high frequency service, missing the advertised headway becomes the sole metric of reliability).
A Way to Compare Tradeoffs
If we add another hour of frequent service somewhere on a line, does it come from reducing headways at other times? Though low-ridership routes or time periods may not justify high frequency service, its important to have a sense for, overall, how frequencies are changing.