.svg) Interstate 505 | ||||
|---|---|---|---|---|
 I-505 highlighted in red | ||||
| Route information | ||||
| Auxiliary route ofI-5 | ||||
| Maintained byCaltrans | ||||
| Length | 32.99 mi[1] (53.09 km) | |||
| Existed | 1977–present | |||
| NHS | Entire route | |||
| Major junctions | ||||
| South end |  I-80 inVacaville | |||
| Major intersections | ||||
| North end |  I-5 nearDunnigan | |||
| Location | ||||
| Country | United States | |||
| State | California | |||
| Counties | Solano,Yolo | |||
| Highway system | ||||
| ||||
Interstate 505 (I-505) is a north–southauxiliary Interstate Highway in theSacramento Valley inNorthern California. It is aspur auxiliary route ofI-5 that runs from nearDunnigan south toI-80 inVacaville. I-505 is primarily a rural Interstate, but travels through Vacaville and the city ofWinters. The highway is the primary route connecting theSan Francisco Bay Area and the northernSacramento Valley, bypassingSacramento and its attendant city traffic. Thus, it is a major route for travelers heading directly from the San Francisco Bay Area to theShasta Cascade and thePacific Northwest.
The entirety of I-505 is defined in section 617 of theCalifornia Streets and Highways Code asRoute 505, and that the highway is from "Route 80 nearVacaville toRoute 5 nearDunnigan".[2] This definition roughly corresponds with theFederal Highway Administration (FHWA)'s route logs of I-505.[3][4]
The southern terminus of I-505 is at I-80 next to theNut Tree Airport in theNut Tree area inVacaville. From there, it travels north about 10 miles (16 km) through rural areas near the western edge of theSacramento Valley before reachingWinters. I-505 then skirts the easterncity limits of Winters, intersecting withState Route 128—the only exit in Winters. After leaving that city, the Interstate then proceeds north through rural areas again for about 20 miles (32 km), including an interchange withCalifornia State Route 16 nearMadison, until it reaches its northern terminus with I-5 nearDunnigan.
For its entire length, I-505 is a four-lane freeway (two lanes in each direction) with a maximum speed limit of 70 mph (110 km/h), which is typical for rural Interstates in California.
I-505 is part of theCalifornia Freeway and Expressway System,[5] and is part of theNational Highway System,[3] a network of highways that are considered essential to the country's economy, defense, and mobility by theFederal Highway Administration.[6]
What is now I-505 was originally conceived as part of a loop Interstate with a directional suffix, I-5W.[7] However, I-5W and most of the other Interstates around the country with directional suffixes were eventually renumbered or eliminated, exceptI-35E andI-35W in Texas and Minnesota.I-69 segmentsI-69W,I-69C, andI-69E in southern Texas have since been designated as well along with proposed suffixed segments for future extensions ofI-14 andI-27 to follow. The former route of I-5W now corresponds toI-580 from I-5 south ofTracy toOakland,I-80 from Oakland to Vacaville, and I-505 from Vacaville to I-5 near Dunnigan.
The northernmost section of I-505, between SR 16 in Madison and I-5 near Dunnigan, opened in August 1977.[8]
| County | Location | mi [9] | km | Exit [9] | Destinations | Notes |
|---|---|---|---|---|---|---|
| Solano | Vacaville | 0.00 | 0.00 | 1A |  I-80 west –San Francisco | Southern terminus; I-80 exit 56 |
| — | Orange Drive / Nut Tree Road | Northbound exit (only accessible from I-80 east) and entrance | ||||
| 1B |  I-80 east –Sacramento | Southbound exit and northbound entrance; provides direct access to East Monte Vista Avenue; I-80 exit 56 | ||||
| 1.45 | 2.33 | 1C |  Vaca Valley Parkway | Signed as exit 1 northbound; servesKaiser PermanenteVacaville Medical Center | ||
| 3.06 | 4.92 | 3 | Midway Road | |||
| | 5.57 | 8.96 | 6 | Allendale Road | ||
| | 10.43 | 16.79 | 10 | Putah Creek Road | ||
| Yolo | | 11.03 | 17.75 | 11 |   SR 128 west (Grant Avenue) / Russell Boulevard (CR E6 east) –Winters,Davis | Eastern terminus of SR 128; western terminus of CR E6 |
| | 14.66 | 23.59 | 15 | Road 29A | ||
| | 17.16 | 27.62 | 17 | Road 27 | ||
| | 21.25 | 34.20 | 21 |  SR 16 –Woodland,Esparto | ||
| | 24.06 | 38.72 | 24 | Road 19 | ||
| | 28.08 | 45.19 | 28 | Road 14 (CR E10) –Zamora | ||
| | 30.74 | 49.47 | 31 | Road 12A | ||
| | 32.99 | 53.09 | — |  I-5 north –Redding | Northern terminus; no access to I-5 south; I-5 south exit 553 | |
| 1.000 mi = 1.609 km; 1.000 km = 0.621 mi | ||||||
