There are a LOT or variables here. Time TOTALLY depends on daily traffic. There are four routes â€“ your address in Pleasanton and destination in Union City will really determine the best route. And keep in mind, these routes vary from day to day with traffic conditions. If you can go during off-commute times, so much the better â€“ you will typically have smooth sailing all the way in both directions (except for the 238 section of the drive).
(1) 580 to 238 to 880-S. Many delays in this route because of the extensive bottleneck and construction on 238. In fact, if there is any way to do so, avoid this route. In addition, 880 southbound is typically very slow during commute hours.
(2) 580 to E-Castro Valley Boulevard, Grove Way to A Street to Foothill to Mission Boulevard south. Lots of lights and slow traffic. There are a number of variables here based on your destination in Union City.
(3) 680 to Fremontâ€™s Mission Boulevard exit, then north on Mission Boulevard. The Sunol Grade is very slow during commute hours, but does have a carpool lane. You can also go down to Auto Mall Parkway, cross over to 880 then go north to Union City. 880 north is congested during commute hours.
(4) 680 to 84 (Niles Canyon Road) then north on Mission Boulevard â€“ this is the scenic route, but is a very temperamental route â€“ accidents, shutdowns from bad weather and jam-ups can be the order of the day.
The Caltrans road widening project is scheduled to be completed early in 2010 and will greatly impact the flow of traffic â€“ see the links below.