This example is a 3.1 miles long segment of I-93 North. It demonstrates segment and lane time of day (TOD) attributes.
In this example, 4 lanes depart from Node 1 and after 1 mile transition to 3 lanes plus a shoulder that is used part time during peak hours. The images below show the highway from a street view and an aerial overview.
The nodes in this example represent the on- and off-ramps to this section of highway.
- Node 1: Upstream on-ramp at Route 125
- Node 2: Downstream off-ramp at Dascomb Road
Table 1: node
| node_id | name | x_coord | y_coord | z_coord | node_type | ctrl_type | zone_id | parent_node_id |
|---|---|---|---|---|---|---|---|---|
| 1 | - | 322919 | 4717100 | - | ramp | yield | - | - |
| 2 | - | 321472 | 4721248 | - | ramp | none | - | - |
The link represents the northbound freeway between the 2 nodes. For the link table, we use the properties that the link has for the majority of its length.
Table 2: link
| link_id | from_node_id | to_node_id | directed | length | lanes | allowed_uses |
|---|---|---|---|---|---|---|
| 1 | 1 | 2 | true | 3.1 | 3 | auto, truck, bus |
*Optional fields left blank for this example are: name, geometry_id, geometry, dir_flag, grade, facility_type, capacity, free_speed, bike_facility, ped_facility, parking, jurisdiction, & row_width
Like the link, we use the lane table to represent the lane configuration of the majority of the link.
Table 3: lane
| lane_id | link_id | lane_num | allowed_uses | r_barrier | l_barrier | width |
|---|---|---|---|---|---|---|
| 11 | 1 | 1 | auto | - | - | - |
| 12 | 1 | 2 | auto, truck, bus | - | - | - |
| 13 | 1 | 3 | auto, truck, bus | - | - | - |
Two segments are needed for this example. The first to represent the 1 mile segment where the link has 4 lanes and the second for the segment where there are TOD changes.
Table 4: segment
| segment_id | link_id | ref_node_id | start_lr | end_lr | lanes | l_lanes_added | r_lanes_added |
|---|---|---|---|---|---|---|---|
| 11 | 1 | 1 | 0 | 1 | 4 | - | 1 |
| 12 | 1 | 1 | 1 | 3.1 | 3 | - | - |
*Optional fields left blank for this example are: capacity, free_speed, bike_facility, ped_facility, parking, allowed_uses
There are two entries for segment lanes. Segment Lane 14 represents the additional 4th lane on Segment 11 and Segment Lane 15 represents the shoulder on Link 12 that has time of day changes.
Table 5: segment_lane
| segment_lane_id | segment_id | lane_num | parent_lane_id | allowed_uses | r_barrier | l_barrier | width |
|---|---|---|---|---|---|---|---|
| 14 | 11 | 4 | - | auto, truck, bus | - | - | - |
| 15 | 12 | 4 | - | shoulder | - | - | - |
The segment_tod table represents the additional lane from the part time shoulder use for Segment 12.
Table 6: segment_tod
| segment_tod_id | segment_id | time_day | timeday_id | lanes | l_lanes_added | r_lanes_added |
|---|---|---|---|---|---|---|
| 120 | 12 | 01111100_1500_1900 | - | 4 | - | 1 |
*Optional fields left blank for this example are: capacity, free_speed, bike_facility, ped_facility, parking, toll
The segment_lane_tod table is used for the change in allowed uses for the part-time shoulder lane.
Table 7: segment_lane_tod
| segment_lane_tod_id | segment_lane_id | time_day | timeday_id | lane_num | allowed_uses |
|---|---|---|---|---|---|
| 150 | 15 | 01111100_1500_1900 | - | 4 | auto, bus |
*Optional fields left blank for this example are: r_barrier, l_barrier, and width