Article · Wikipedia archive · Last revised Jul 26, 2026

Arroyo Simi Overhead

The Arroyo Simi Overhead is a tall viaduct in Ventura County, California, that carries State Route 118 over the Arroyo Simi. At the south end of the bridge, the freeway continues as SR 23. The state routes continue as highways to the west and north respectively. The entire connector, completed in 1993, is 2.2 miles (3.5 km) long and includes seven bridges.

Last revised
Jul 26, 2026
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≈ 2 min
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Citations
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Source
Arroyo Simi Overhead
Coordinates34°17′13″N 118°51′53″W / 34.28694°N 118.86472°W / 34.28694; -118.86472
Carries4 lanes of SR 118
CrossesArroyo Simi
LocaleMoorpark, California
OwnerCaltrans
Maintained byCaltrans
Characteristics
DesignDual-span viaducts
MaterialConcrete
Total length538 metres (0.334 mi)
Width14 metres (46 ft)
13 metres (43 ft)
History
Constructed byC. C. Myers (bridges)
C. A. Rasmussen (roadwork)1
Construction startApril 19, 19912
OpenedOctober 15, 1993 (October 15, 1993)34
ReplacesLos Angeles Avenue56
Location
Map
Interactive map of Arroyo Simi Overhead

The Arroyo Simi Overhead is a tall viaduct in Ventura County, California, that carries State Route 118 (SR 118, Ronald Reagan Freeway) over the Arroyo Simi. At the south end of the bridge, the freeway continues as SR 23.7 The state routes continue as highways to the west and north respectively. The entire connector, completed in 1993, is 2.2 miles (3.5 km) long and includes seven bridges.28

The railroad line between Simi Valley and Moorpark together with a local road also pass under the two main 100-foot-high (30 m) bridges that separately carry the traffic in each direction, each more than 1,400 feet (430 m) long.12 A wetlands was created as a mitigation measure for the impacts of the construction on the Arroyo Simi. Nearby Moorpark College manages and maintains the site which is used as a nature center by the environmental science program.9

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