Data Dictionary (2008)
*Note TriMet has updated their BDS in 2014
The following is a data dictionary describing the fields in the TriMet BDS card data.
This column indicates the calendar date associated with service (date vehicle leaves garage).
Each bus has a unique identification number. The vehicle numbers of our fixed-route buses generally correspond to characteristics such as high-floor vs. low-floor, vehicle length, etc. In general, low-floor buses are numbered 2001-2099, 2201-2399, then 2501 and greater. All buses are 40', except for vehicles numbered 1124-1126 (Ford vans), 1601-1643 (30'), 1901-1910 (30'), 2401-2418 (27').
TRAIN OR BLOCK
Scheduled trips for a single vehicle are grouped together into blocks (trains) for assignment.
Badge refers to operator identification number.
Route number is the numeric designation for the route.
The following diagram
refers to the variables arrive time, leave time, dwell time and stop time. All
times at TriMet are calculated in seconds post midnight. The GPS-equipped buses
calculate their position every second, with a spatial accuracy that is greater
than plus or minus 10 meters. Successive positions are weeded and corrected
by odometer input.
When the bus is within 30 meters of an accurate location of the next bus stop that is stored on the data card with the schedule, an arrive time is recorded. The arrival time is recorded at all stops even if the bus doesn’t stop to serve passengers. In the event of passenger activity at the stop, the time that the bus enters the stop circle is overwritten with the time of door opening.
When the bus is no longer within 30 meters of the bus stop location a departure time is recorded. The departure time is recorded at all stops even if the bus doesn’t stop to serve passengers.
If the door opens to serve passengers, a dwell is recorded, and the arrival time is overwritten by the time when the door opens. Dwell time (in seconds) is recorded as the total time that the door remains open.
Stop time is the time a bus is to scheduled to depart a given location. TriMet writes schedules to time points rather than individual stops. For example, a scheduled time of 12:34:00 means that a bus is supposed to depart a given location at that time.
This number is either 1 or 0. A value of 1 refers to the inbound direction and 0 refers to the outbound direction. For crosstown routes, direction is still defined but does not refer to movement relative to the location of the Central Business District.
This indicates day type such as weekday, Saturday, Sunday or holiday.
W = weekday
S = Saturday
U = Sunday
X = holiday
It is the sequential numbering of scheduled trips by direction.
Location is is the unique identification number of a bus stop. If the stop is an unscheduled stop then the number is either the stop before or the stop after depending on the location of the bus at the time of the unscheduled stop.
The value for door opening ranges from 0 to 2.
0 = no door was opened
1 = front door was opened
2 = both front and rear door was opened
Lift refers to lift operation. If the lift was used then the value is 1 and if it was not used then the value is 0.
This variable refers to the number of boarding passengers at a stop.
This variable refers to the number of alighting passengers at a stop.
This variable refers to the estimated passenger load at each stop. Loads are estimated from boarding and alighting information during post-processing of the BDS card data. The post-processing algorithm performs accuracy checks based on APC beam counts. If the APCs are deemed accurate, then the algorithm balances passenger loads on a per-vehicle basis over the course of a given service day.
This variable refers to the maximum speed of the vehicle since the previous bus stop.
Cumulative actual miles traveled by the vehicle (train) since it left the garage.
Linear scheduled distance measured from beginning of the route to the current location. The variable is based on service pattern and is non-cumulative.
Location distance is the distance between actual GPS vehicle position and static GPS location of scheduled stop.
X COORDINATE, Y COORDINATE
The X and Y coordinates are the latitude and longitude coordinates using the State Plane Coordinate System (NAD83, Oregon North).
0 = row added during post-processing.
1 = stop, but not location ID, recorded by vehicle.
2 = stop and location ID recorded by vehicle.
This field flags stop activity in relation to the schedule.
0 = off-trip stop
1 = unscheduled stop
2 = regular stop
3 = pseudo stop (unofficial time point)
4 = time point (official time point)
5 = first stop in trip
6 = last stop in trip
This field flags the quality of APC readings and contains the values N, G, or B.
N = bus is not equipped with APC
G = APC readings are flagged as good
B = APC readings are flagged as bad
Thursday, September 25, 2014 10:16 AM