California Touge.Best driving roads in California

Mount Umunhum Road

A summit-access road with tight turns and broad valley views. Preserve opening hours apply.

Low speedDifficulty 3/3 · DemandingSouth Bay

Road shape

Length
5.4 mi
Bends
56
Switchbacks
10
Bends per mile
10.3
Turning per mile
1131°
Curviest rank
5of 85

Measured from the OpenStreetMap centreline at a 20 m sampling step — road shape only, not a safety or speed judgement. How bends are counted.

Elevation

Low 1,400 ft5.5 miHigh 3,466 ft
Total climb
2,206ft
Climb per mile
409ft
Highest point
3,457ft
Steepest grade
12.5%

Sampled every 100 m from USGS 10 m elevation data, a public-domain federal dataset. Total climb counts vertical change in both directions, so it does not depend on which way you drive. How elevation is measured.

Speed limits

25 mph

Published limits

Lower speeds may be needed at bends. Follow posted signs.

Midpen’s 2016 road rehabilitation sign plan specifies 25 mph signs. Current signs take precedence.

Speed-limit source ↗

Posted signs always govern. How speed evidence is handled.

Sources

Difficulty 3/3 (Demanding) is our editorial rating of width, bends and sightlines; “Low speed” describes character, not a target speed. Full method. Identified from:

Reviewed 2026-09-08. The trace shows selected road sections, not a navigation route.

Roads nearby

View on the Bay Area map →Check road conditions ↗Open in Google Maps ↗All 85 roads →