Reading Road Surface Condition Codes

Road surface condition codes are available via the Synoptic API by including road_surface_condition as a requested variable. This variable is reported by Road Weather Information System (RWIS) stations, commonly part of state Department of Transportation (DOT) networks.

An API response including this variable might look like:

road_surface_condition_value_1: {
date_time: "2020-01-06T22:36:00Z",
value: 9

The following table provides descriptions for each code value.

Road Surface Condition Code Values

Note that some descriptions are repeated, due to the history of different road sensor types outputting different numeric codes.

Code Description
0 No Report
1 Dry
2 Trace Moisture
3 Moist
4 Wet
5 Chemically Wet
6 Ice
7 Frost
8 Snow
9 Slush
11 Dry
12 Trace Moisture
13 Wet
14 Chemically Wet
15 Ice Watch
16 Ice Warning
17 Frost
18 Snow Watch
19 Snow Warning
21 Snow/Ice Watch
22 Snow/Ice Warning
23 Wet Below
24 Damp
25 Absorption
26 Error
27 No Report