§ 91.11 What abbreviations for NTD modes are used in this Manual?

CB.  Commuter bus – Fixed-route bus systems that are primarily connecting outlying areas with a central city. Service typically uses over-the-road buses with service predominantly in one direction during peak periods, limited stops, and routes of extended length.

CC.  Cable car – A railway propelled by moving cables located beneath the street. While popular at the turn of the last century, the only surviving system is operated in San Francisco.

CR.  Commuter rail – Rail service operating on either old freight railways, or on tracks that are shared with freight railways, Amtrak, or both. The service is characterized by relatively long distances between stops, for service primarily connecting a central city with outlying suburbs and cities. The service may be either diesel or electric-powered and usually has grade-crossings with roadways.

DR.  Demand response – Shared-ride demand response service is scheduled in response to calls from passengers. Many transit systems operate demand response (DR) service to meet the requirements of the Americans with Disabilities Act (ADA).

DT.  Demand response – Taxi – A special form of the demand response mode operated through taxicab providers. The mode is always purchased transportation type of service.

HR.  Heavy rail – An electric railway that operates local service in exclusive right-of-way. The service is characterized by long trains of six to eight cars or more and by relatively short distances between stops for local service within a city and the immediate suburbs. The Nation’s traditional subway systems are classified as heavy rail.

JT.  Jitney – A transit mode comprising of owner-operated passenger cars or vans operating on fixed routes (sometimes with minor deviations) as demand warrants without fixed schedules or fixed stops.

LR.  Light rail – An electric railway that operates local service in mixed traffic with road vehicles, or has grade crossings with roadways. The service is characterized by short trains of one to four cars and by relatively short distances between stops for local service within a city and the immediate suburbs.

MB.  Bus – Fixed-route bus service is the most-prevalent mode in the country. MB service is powered by a motor and fuel contained within a vehicle. Deviated fixed-route service is also reported as MB.

MG.  Monorail and automated guideway – An electric railway that straddles a single guideway. It may have vehicle operators or may use computers to guide the vehicles.

PB.  Público – Publicos are jitney services operated in Puerto Rico. A transit mode comprising of passenger vans or small buses operating with fixed routes but no fixed schedules. Publicos (PB) are a privately owned and operated public transit service which is market oriented and unsubsidized, but regulated through a public service commission, state or local government. Publicos (PB) are operated under franchise agreements, fares are regulated by route and there are special insurance requirements. Vehicle capacity varies from eight to 24, and the vehicles may be owned or leased by the operator.

RB.  Bus rapid transit – Fixed-route bus systems that either (1) operate their routes predominantly on fixed-guideways (other than on highway high occupancy vehicle (HOV) or shoulder lanes, such as for commuter bus service) or (2) that operate routes of high-frequency service with the following elements: Substantial transit stations, traffic signal priority or preemption, low-floor vehicles or level-platform boarding, and separate branding of the service. High-frequency service is defined as 10-minute peak and 15-minute off-peak headways for at least 14 hours of service operations per day. This mode may include portions of service that are fixed-guideway and non-fixed-guideway.

SR.  Streetcar rail – Rail systems operating routes predominantly on streets in mixed-traffic. This service typically operates with single-car trains powered by overhead catenaries and with frequent stops.

TB.  Trolleybus – Fixed-route service using rubber tire buses powered by electric current from overhead wires using trolley poles. Service using rubber tire replica trolleys or historic trolleys, powered by an on-board motor are not included in this mode.

TR.  Arial tramway – A system of aerial cables with suspended vehicles.

VP.  Vanpool – A commuting service operating under prearranged schedules for previously formed groups of riders in vans.

YR.  Hybrid rail – Rail systems primarily operating routes on the National system of railroads, but not operating with the characteristics of commuter rail. This service typically operates light rail-type vehicles as diesel multiple-unit trains (DMU’s).