I am driving from Mountain View, California to Concord, California
tonight (a Friday).  I want to be in Concord by 7PM.  I don't want to
be late, but I also don't want to leave too early.  When should I
leave Mountain View.

I know how to get there in general (101-237-680) and I know this route
takes a bit over an hour when there is no traffic.  However, I don't
know the rush hour traffic, so I don't know how much longer it takes
when there is traffic.  I've also heard that Fridays are worse and
rush "hour" starts earlier.

Hi Steve,

Firstly, here are some possible routes that were generated by
MapQuest. I think you'll find this helpful to refer to:

http://www.mapquest.com/directions/main.adp?go=1&do=nw&2n=Contra+Costa&ct=NA&1ex=1&1y=US&1a=&1p=&1ac=EHsq%252fLZrlKKZ4km%252fEw4Xajq%252b58QLDAgXSk16iPHx80nsHzXYXKRmcXHh%252b5jsBRt%252bq2Eb8pd30XY%253d&2y=US&2a=&2p=&2c=Concord&2s=CA&2z=&lr=2&x=70&y=17

You'll notice MapQuest estimates 1 hour and 10 minutes on the fastest
route...while I suggest using this route, you will NOT be travelling
at the speed limit.

Having travelled between these two locations at various times of day,
I have estimated that "rush hour" traffic in general slows the route
down by about 40-60% compared to optimal travel times (middle of the
night). That said the estimated time increases to between 1 hour 30
min and 2 hours.

It is true that Fridays are the worst...rush hour tends to start about
30 minutes earlier than the normal 4PM and for some reason are heavier
throughout. My recommendation, then, is to take the upper end of the
scale and increase your time allowed by 60% of the listed time.

This comes out to 112 minutes, which for you means leaving at 5:08PM.
Considering its a summer and more people are on the road, lets just
play it safe and make sure your on the listed route at about 5PM :)

Enjoy your trip and thanks for using Google Answers!

answerguru-ga

---

Clarification of Answer by answerguru-ga on 02 Aug 2002 14:22 PDT

Steve,

To clarify the "quibble" you pointed out:

If the route slows down by 40-60%, then this is the same as travel
time increasing by the same amount..

You did interpret this correctly, so everything should be fine :)

answerguru-ga

Since the answer wasn't available on line (or at least I couldn't find
it, and appearently neither could you), I needed someone with personal
experience, and that is what I got.

One quibble with the statement - "rush hour" traffic in general slows
the route down by about 40-60% compared to optimal travel times.  It
seems as if what you meant was - "rush hour" traffic increases the
travel time by about 40-60% compared to optimal travel times - since
this is the calculation you gave.

I hope you are right.

You might want to check this to make sure there aren't any major incidences.
(look for "Bay Area" in menu, click on "both")

http://cad.chp.ca.gov/