Update Speed Limits of Center Line Data

[tnjtr2]

Update SL Process

Preparing Data

1. Export SL a. Skip S SL signs since they're only when children are present, and we want to overestimate how fast people might be driving
2. Reduce Text field to just the SL number
3. Create a numeric Speed Limit field (not sure if this was necessary) by using field calculator
4. Spatially join the Sign layer to the Centerline layer, and create a sandbox shapefile
5. Select the Centerline segments which are within the city boundaries, and maintained by Madison a. Export into a new centerline layer with fewer entries
6. Go through all the unexpected Maintained By values, and remove those which don't have signs along them
7. Go through higher functional classes, and remove those which don't matter, like parking lots and alleys (9s and 7s)

Reviewing Data

1. Advanced sort the attribute table of the whittled down Centerlines a. Centerline Speed Limit by descending, functional class by ascending, segment_na by ascending, mslink by ascending
2. Select by attribute the centerlines where the recorded Speed Limit doesn't match that of the nearest sign
3. Go through and edit the original centerline speed limit
4. Find the "TE_SLTruckRouteFnctClassMaster Table"
5. Join the modified centerline data to the "TE_SLTruckRouteFnctClassMaster Table" based on the mslink
6. Make the table speed limit match the new edited speed limit

[tnjtr2]

When reviewing Speed Limit data

• Look before the segment in each direction of travel for Speed Limit signs
• Overwrite "Centerline Speed Limit" value, or "Sign Speed Limit" value depending on which is incorrect
• Where there is a different speed limit for each direction of travel OR where the speed limit changes part way through the segment, record the higher speed limit
  • Record the lower speed limit in the newly created "2nd Centerline Speed Limit" field
  • The exception to the above rule is if a speed limit sign is posted immediately following the intersection on a oneway segment, in which case apply the posted speed limit for vehicles turning onto that street
    • OR bidirectional segments with matching speed limit signs at each intersection

[tnjtr2]

• [ ] Update TE_SLTruckRouteFnctClassMaster table