I often wonder if governments really focus on the issues rather than responding to incidents. In the case of pedestrians and the City of Sacramento, is the city really placing its attention, and its dollars, where they need to be to enhance the safety of pedestrians? I’ve created some maps to show where the problems lie (see note at bottom about data sources and how these were created).
The collisions mapped are:
- Date: 01-01-2004 to 12-31-2012
- Location: City of Sacramento only (no, I can’t explain why some are outside the city)
- Victim role: Pedestrian
- Victim degree of injury: Killed or Severe Injury
- 388 collisions
- ArcGIS link
The first map, a point map of the entire city, shows:
- the greatest density of collisions is in downtown/midtown, but there are certainly plenty in other areas
- almost all collisions happen at intersections, not mid-block
- almost all collisions are associated with major streets, called arterials and collectors, which are wide and high speed, intended to move motor vehicle traffic at speed rather than provide for multi-modal transportation
The next map is a heatmap of the same area, and provides a more visual indicator of patterns.
The three maps below zero in on each of the three “hottest” areas of downtown/midtown, south Sacramento, and north Sacramento. In downtown/midtown, the highest concentrations are around 20th St between J and L, on Broadway from 18th to 20th, and J St at 5th and 6th. It would take more study to say anything definitive, but I’ll speculate:
- 20th St: a large concentration of bars
- Broadway: light rail station generates a lot of pedestrian traffic
- J St: a lot of people going to and from Sacramento Valley station while crossing high speed traffic on J St exiting the freeway but not yet slowing down
In north Sacramento, the highest concentrations are at near the intersection of El Camino and Del Paso, and along Arden near Royal Oaks. Again, speculating:
- El Camino and Del Paso: high speed roadways (almost all traffic is traveling over the speed limit of 35 mph) with skewed intersections that reduce visibility and increase crossing distances for pedestrians
- Arden: light rail station generates a lot of pedestrian traffic
In south Sacramento, the concentrations are Broadway and 39th St, and the intersection of Stockton Blvd and Fruitridge Rd. Again, speculating:
- Broadway: a high school on the north and a multi-family complex on the south, with a skewed intersection of Broadway and Martin Luther King that pedestrians might avoid
- Stockton and Fruitridge: a high school, a large number of businesses on all four corners of the intersection, high speed traffic exceeding the speed limits of 35 mph on Stockton and 40 mph on Fruitridge, and a neighborhood in which many people walk for economic reasons
There are also a number of other concentrations, and the pattern is dispersed, probably indicating a lot more people walking for daily transportation purposes than in other parts of the city.
My next steps in looking at data and patterns would be to:
- see if there are differences in the concentration areas between the killed and severe injury categories
- look more closely to determine whether more collision are occurring right at intersections, meaning with marked or unmarked crosswalks, or at mid-block locations
- determine whether pedestrian fault or motor vehicle driver fault varies with geography (note: law enforcement officers often blame pedestrians, and take with word of the motor vehicle driver when the pedestrian did not survive, so this indication should always be taken with a grain of salt)
- create an overlay of where the city is doing projects to enhance pedestrian safety, to see if they are putting efforts where needed; unfortunately, the city doesn’t make this information readily available so it would take time to compile
TIMS (Transportation Management Information System) makes data from SWITRS (California Statewide Integrated Traffic Records System) available to the public. In order to use the system, you have to create a TIMS account, but they are free. The easiest interface to use is the SWITRS GIS Map. The tools creates three types of maps: point, cluster (number of collisions in near proximity), and heatmap. However, the cluster and heat maps cannot be printed so far as I can tell, so I have exported the data and used ArcGIS to create the maps. This product from ESRI also requires a personal account to use, but they are free.