¶ Features
The primary mission of Safety in Numbers is to build a map of road safety devices. In order to do this we have defined a standard set of features to identify on the roads.
This list is focused on the features used on roads in the United States, but in time we hope to expand this feature list to cover devices, signs, and markings from around the world.
Please see the page on data sources for information on how the list of features is compiled and our sources.
¶ Vehicle Barriers
These are variable length barriers designed to prevent a car that is leaving the road from hitting a hazard - perhaps going over a cliff, striking a tree, or crossing the interstate into oncoming traffic.
We seperate them into categories mostly based on what they are made from:
You can see more detail regarding the specific data fields common to all barriers and the data sources we draw from on the vehicle barrier page.
¶ Terminals
Terminals are safety devices of a fixed length designed to reduce the damage done when a vehicle leaves the road. They include:
EndTerminal- caps on guardrails and other barriersCrashCushion- free standing cushions placed in front of fixed hazards like signs and bridge supportsBluntEnd- unprotected barrier ends
You can see more detail regarding the specific data fields common to all terminals and the data sources we draw from on the terminal page.
¶ Official Signs
We track all official road signage across the United States. To make it easier for users to find signs we've broken them up into categories:
¶ Crashes
We track anonymous historic crashes as Features. We collected these crashes from a variety of data sources and group them in categories based on the type of damage that occurs.
You can see more detail regarding the specific data fields common to all crashes and the data sources we draw from on the crash page here.
¶ Road Surface Features
Physical features on the road surface, like rumble strips, and speed bumps play a major role in preventing accidents. We categorize them first as points and lines and then into broad groups.
Point Features:
Line Features:
You can see more detail regarding the specific data fields and the data sources we draw from on the feature page.
¶ Road Surface Markings
These are markings painted or adhered to the road surface. They include lane markings and a variety of other signage. We categorize them first as points and lines and then into broad groups.
Point Features:
ArrowLeft- Left turn arrowArrowRight- Right turn arrowArrowSplitLeftOrStraight- Left turn or Straight arrowArrowSplitRightOrStraight- Right turn or Straight arrowArrowStraight- Straight arrowCrosswalkZebra- Pedestrian crossingGiveWayRow- Yield markings in a lineGiveWaySingle- Single yield markingStopLine- Hard line representing a stop pointSymbolBicycle- Bicycle markingText- Written textOther
Line Features:
You can see more detail regarding the specific data fields and the data sources we draw from on the feature page.
¶ Access Points
Access points denote the locations where vehicles can join a road way. We do not currently differentiate between the different kind of access points.
You can see more detail regarding the specific data fields and the data sources we draw from on the feature page.
¶ Official Cameras
Cameras are specifcally traffic cameras - including speed, red light, and general monitoring cameras. This category is not further differentiated given the difficulty of visually determining the difference between these camera types.
You can see more detail regarding the specific data fields and the data sources we draw from on the feature page.
¶ Signals
We track traffic related signals (e.g. stop lights, walk lights., but not in particular detail at this time. We have three
You can see more detail regarding the specific data fields and the data sources we draw from on the feature page.
¶ Fences
We track a few specific types of fencing that directly impact road safety. Specifically:
You can see more detail regarding the specific data fields and the data sources we draw from on the feature page.
¶ Other
If a given feature you wish to mark is not listed you are welcome to mark it using the Other point or line features. Describe what you have marked in the notes.
Safety in Numbers reviews Other entries intermittently when we go to make additions to the feature list.
You can see more detail regarding the specific data fields and the data sources we draw from on the feature page.
¶ Work Zone Devices
We are not currently tracking any work zone devices because they are temporary.