If you are developing a property on a roadway that is controlled by the Texas Department of Transportation (TxDOT) and want to maximize access, you will have to consider standards on TxDOT driveway spacing. This is one of the criteria that TxDOT will assess your access driveway permit application.

Why does driveway spacing matter?

We often are taught to keep a “two-second distance” between ourselves and the car in front of us. The intention is that we will have the distance and time to react should they behave unexpectedly. But this is an overgeneralization since a driver’s reaction time and their appropriate stopping distance varies not just with the speed which you and the rest of traffic are going, but also physical factors such as the effectiveness of your vehicle’s brakes, incline or the road, traction, and other conditions.

Traffic and transportation engineering takes many variables and produces a design that keeps you and me safe on the road. These design principles become design criteria much like TxDOT driveway and access road spacing requirements.

What are the driveway spacing requirements?

The distance between driveways are measured from the edges of the pavement of the driveway, prior to the return radius.

How far your TxDOT driveway and access road will need to be designed varies directly with the type of road your development lies on and the posted speed (this differs from a roadway design speed, which can often be higher than the speed limit). Let’s break it down by road type:

Freeway Mainlanes

Access to properties along Freeways is generally not allowed from mainlanes and require an interchange or entrance and exit ramps to frontage roads which then provide access to properties.

Freeway Frontage Roads

Frontage roads typically are aligned parallel to freeway main lanes and connect properties from freeway interchanges and arterial roads that tie-in to the frontage.

Frontage Driveway Spacing Requirements
Minimum Driveway Spacing Requirements for TxDOT Owned Frontage Roads

Other State Highways

State system highways that are not freeways or rural highways with Annual Average Daily Traffic (ADT) volumes below 2000 (which require more traffic analysis for permitting).

Highway Driveway Spacing Requirements
Minimum Driveway Spacing Requirements for TxDOT Owned Highways

Exceptions and Variances

These distances assume the highway approach to the driveway is on level grade. If there is a downslope or upslope present, the permitting team may require a greater or lower spacing distance.

TxDOT further divides its jurisdiction into districts, that are given authority to amend these rules as needed for their regions. The department also enters into agreements with some municipalities to create special access standards that are more appropriate to their local communities.

If your development cannot meet these minimum requirements, then a variance may be required. The variance process is initiated during the driveway application process and is approved by the TxDOT permitting team. A variance often comes with special performance or design criteria for the driveway and development in question. Emergency access driveways and field driveways are also permitted on a case by case basis.

There are two automatic exceptions to spacing requirements:

  • If a TxDOT construction or improvement activity causes a property to otherwise become “land-locked”. This exception does not apply to properties that have become land-locked due to a subdivision and will often require properties to share access to existing driveways or shared access drives.
  • Existing driveways that are rendered inaccessible due to highway construction.

If you are developing a property and need assistance securing an approved permit for an access driveway on a TxDOT Right of Way, our traffic and site permitting experts can prepare and expedite your permitting process. Contact me at BIG RED DOG Engineering by emailing me at shaun.theriot-smith@bigreddog.com or calling 1-877-733-3642