Simpson Lane Climb
- long (7.0 km)
- 4.3 mi
- long (7.0 km)
- of climbing (258 m)
- 846 ft
- of climbing (258 m)
- average grade
- 3.7%
- average grade
- steepest 500 m
- 9.9%
- steepest 500 m
Elevation profile
From 79 ft at the bottom to 925 ft at the top. Grades are averaged over each half kilometre, from USGS elevation data, so short ramps can be steeper than they show.
Weather at the top of Simpson Lane this week
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Is it safe to bike up Simpson Lane?
We don't rate roads as safe or unsafe: crash counts can't say how risky a ride is, and roads people like to ride draw more riders, so they see more crashes. What the records show: 2 bike crashes were reported on or beside Simpson Lane along the climb from 2021–2025.
Common questions about Simpson Lane
- How long and steep is the Simpson Lane climb?
- 4.3 miles (7.0 km) at 3.7% on average, climbing 846 ft (258 m) from 79 ft to 925 ft. The steepest half kilometre averages 9.9%. That makes it a Category 3 climb.
- Where does the climb start and finish?
- It starts at 39.41232, -123.80809, where Simpson Lane leaves Shoreline Highway, and tops out on the road at 39.38112, -123.75244.
- Is Simpson Lane paved?
- Mostly: OpenStreetMap tags 85% of the climb as paved, and the rest as dirt or gravel.
- How is the category worked out?
- From the climb's shape only: length in metres × average grade (%) of 16,000 or more for Cat 3, 32,000 for Cat 2, 64,000 for Cat 1 and 80,000 for HC. It describes how hard the climb is, not traffic or crashes.
- Where does this data come from?
- The climb is found from OpenStreetMap roads and USGS 3DEP elevation (every climb, not a list of famous ones). Access is from OpenStreetMap tags; gates and closures change, so obey posted signs. Crash counts are police reports in the California Crash Reporting System (CCRS) on data.ca.gov, counted where their map location is within 100 ft of the climb. The forecast is from the National Weather Service.
Other climbs nearby
- Fort Bragg-Sherwood RoadCat 3 · 3.2 mi at 3.5% · 597 ft · starts 2.6 mi away
- Company Ranch RoadCat 3 · 1.5 mi at 6.9% · 535 ft · starts 5.7 mi away
- Riley Ridge Road near Fort BraggCat 3 · 1.4 mi at 9.5% · 719 ft · starts 6.7 mi away
- Ramsey Ridge RoadCat 2 · 6.9 mi at 3.6% · 1,322 ft · starts 6.9 mi away
- Riley Ridge Road near Fort BraggCat 3 · 1.9 mi at 5.8% · 577 ft · starts 7.7 mi away
- Little Valley Haul Road near Fort BraggCat 3 · 2.3 mi at 8.8% · 1,047 ft · starts 8.4 mi away
- Little Valley Haul Road near Fort BraggCat 3 · 4.1 mi at 3.1% · 682 ft · starts 10 mi away
- Docker Hill DriveCat 3 · 1.7 mi at 9.4% · 860 ft · starts 13 mi away
Found from OpenStreetMap roads and USGS 3DEP elevation; ranked on shape only. Category 3: length in metres × average grade (%) of 16,000 or more for Cat 3, 32,000 for Cat 2, 64,000 for Cat 1 and 80,000 for HC. It describes how hard the climb is, not traffic or crashes. Crashes: bike crashes reported within 100 ft of the climb, 2021–2025, from the California Crash Reporting System (CCRS), counted only where the report has map coordinates. Weather: National Weather Service. Access from OpenStreetMap tags; obey posted signs. How the data works.