Accelaration Lane required for Driveway Ingress/Egress

[damialok]

Hi
We have a project thats subdividing the parcel into 2 lots and providing a common 16-20' driveway. The street the driveway is connecting to is curving and also coming from a higher grade. Please see attached picture. Ignore the street width of 32' in the pic, we are proposing 16'-20' driveway now.

The city wants us to create an acceleration lane for about 400' due to sight distance issues. This is big deal because widening the street requires moving 6-7 utilities, electric poles, trees and sidewalks.

What I am looking to see if its even required for a private driveway serving two homes. Also the oncoming traffic's posted speed limit is at 35mph while 85 percentile is at 41.5mph with a traffic count of 6000.

If its(accl lane) required, are there any other strategies(lower cost) available to mitigate this issue?

Thanks and appreciate your feedback.
I am also looking for a Civil engineer who can create a tentative parcel map for this 2-lot sub-division in Fremont, CA. Please email me if you are interested.

 

[MiketheEngineer]

Buy a stoplight??

 

[civilman72]

As far as whether this is "required," that comes down to the local standards. Make them show you where it's required.

While the traffic numbers are fairly high, having an acceleration lane for a speed limit of 35 MPH seems unnecessary, in most cases.

I would have an engineer determine the exact entering sight distance. Then, using standard reaction times and acceleration rates, if the engineer can prove that the through traffic will only be slowed down by less than 10mph (which I believe is considered acceptable by normal standards), it may be acceptable to the review agency.

 

[fattdad]

do you need a special conditional use or zoning permit to subdivide the land for two houses? If so, they the city may have the right to impose such a condition. I would check your state DOT requirements though. . .

f-d

¡papá gordo ain’t no madre flaca!

 

[brandonbw]

We almost had to do something like this on a proposed apartment complex property. Ended up the city didn't require the lane after all. A lot of utilities were going to be moved as well.

B+W Engineering and Design
Los Angeles Civil Engineer and Structural Engineer

http://bwengr.com

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