There is no direction of travel available in crash database. Therefore, the table SMS_CRS_VEHICLE is used to obtain the vehicle direction information and work as a surrogate of direction.
The logic behind identifying the direction of travel is shown in Figure 1 and Figure 2, respectively.
Figure 1 Decision Tree- Direction of Travel for Single Vehicle Crash
Figure 2 Decision Tree- Direction of Travel for Multi-vehicle Crash
A function SMS_TRAVEL_DIRECTION is used that can take the crash ID as argument and returns the travel direction based on the logic provided.
It is important to note that roadway description attribute is obtained from vehicle table. The code values are shown below:
- 1-Two-Way, Not Divided
- 2-Two-Way, Not Divided w/ Continuous Left Turn Lane
- 3-Two-Way, Divided, Unprotected Median
- 4-Two-Way, Divided with Median Barrier
- 5-One-Way Roadway
