by: Eric Burtzlaff, PE
If you are planning to build a private home in Jefferson County, Colorado, I’m sure you have more than a few questions regarding the process. Approval from Jefferson County’s Planning and Zoning Department can be a taxing exercise for even the most seasoned engineers.
In my experience, one of the most important aspects from the Jefferson County’s perspective is your driveway design. The Jefferson County Standards on your driveway will push much of the location of your home, as well as the safety of egress and ingress in the slippery winter months. With that in mind, this article will discuss the Standards on your driveway from Jefferson County and elaborate on exactly why these requirements exist.
The driveway standards are as follows:
Rules of Thumb: Maximum of 10% slope (12% if south aspect); 14-ft width (10-ft paved)
A private driveway in Jefferson County may not be steeper than 10% grade or 10:1. This restraint is in place to avoid creating a slip and slide or unpassable driveway during the Colorado winter.
There is an exception in place for this standard. If your proposed driveway is naturally a southern facing driveway, you are allowed to go up to 12% grade. This is due to the your driveway receiving ample sun exposure and theoretically a faster ice melt. This standard also exists to allow safe travel of your driveway for any emergency vehicle which might need to get your residence.
Your driveway is required to be 14 feet wide throughout the entirety of the drive. The county requires a minimum 10′ all-weather travel surface as well as minimum 2′ shoulders on each side of the drive. You might think that this standard exists solely to allow two cars pass one another on your driveway. However, this standard is actually driven by fire safety. This is the minimum width for a fire truck (or other emergency vehicle) to access your home via your driveway.
The all-weather surface that this standard refers to can be gravel, asphalt, concrete or any other material you can manage to convince the fire department will hold the weight of their trucks.
Your driveway must also not have any radii less than 30′ at the centerline of your driveway.
This again is driven mostly by fire code. A fire truck is going to have a really hard time making any turn tighter than this standard. Also, this standard exists to prevent obscene hairpin turns on Jefferson County driveways. In the winter, such hairpin turns can spell real disaster when your truck start sliding down your drive.
There are a few exceptions to the rules. Firstly, if your driveway is under 50′ in length, none of these rules apply! Secondly, if your driveway is over 150′ in length, you are required to install a firetruck hammerhead (or turnaround) every 150′ of your drive. This allows the emergency vehicle that’s coming to your home to turn around if necessary.
I know my clients tend to get frustrated when I explain that their driveway won’t work the way they envisioned per the Jefferson County code. Just remember that these standards are really in place for your safety whether that be your winter safety or your safety in the event of a fire (or other emergency). You’ll be happy you followed these standards if you ever do come face-to-face with such an event.
Please see Jefferson County Roadway Design & Construction Manual, Section 3.7.8 to see these standards as written by Jefferson County.