California Stabilized Construction Entrance/Exit TC-1
In California, the Clean Water Act is administered through the State Water Resources Control Board (State Water Board) and the nine Regional Water Quality Control Boards (Regional Water Boards), collectively known as Water Boards. CASQA is a professional association that develops widely used BMP guidance and training resources that support stormwater permit compliance in California.
The Water Boards issue NPDES Stormwater Permits, also called waste discharge requirements (WDRs), that regulate discharges to waters of the United States. Construction and industrial stormwater permit coverage generally requires a SWPPP that identifies BMPs, while MS4 operators comply through a municipal stormwater program. Operators of qualifying construction projects, regulated industrial facilities, and MS4s must obtain coverage under the applicable stormwater permit.



CalTrans SWPPP and BMP Resources
The California Department of Transportation (Caltrans) has developed comprehensive stormwater and water pollution control resources that guide Caltrans staff and highway contractors through the planning and permitting. SWPPP and WPCP template, SWPPP/WPCP Preparation Manual, and a BMP Handbook that includes techniques to mitigate pollution.
The BMP Handbook includes detailed specifications for pollution prevention techniques that can be implemented to meet NPDES requirements. BMPs can provide contractors with recommendations on maintenance schedules and guidance on proactively addressing common issues.
BMP handbooks can provide contractors with recommendations about maintenance schedules and information on being proactive about common issues.
Stormwater Details and Drawings: TC-1 Stabilized Construction Entrance/Exit
Section 6.1 of the Construction Site Best Management Practices (BMP) Manual is referred to as the TC-1, or Trackout Control 1. The TC-1 outlines applications, limitations, and techniques for stabilizing temporary construction entrance/exit points on the job site to prevent dirt or mud from being tracked onto public roads. Two types of construction entrances are mentioned. Type 1 is an aggregate-based entrance, while type two is a hybrid construction entrance consisting of aggregate and steel plates. Drawings of Type 1 and Type 2 entrances are provided in the handbook.
A temporary construction entrance/exit is defined by a point of entrance/exit to a construction site that is stabilized to reduce the tracking of mud and dirt onto public roads by construction vehicles. - CalTrans BMP Handbook TC-1
Construction Entrance/Exits minimize sediment tracked off the job site onto impermeable roadways, which are then washed into storm drains. Sediment leaving job sites is often contaminated with oil and toxic compounds, and this contamination should be contained.
CalTrans specifies that traditional aggregate-based tracking pads should consist of crushed rock between 3 inches and 6 inches in size, placed over a geotextile fabric. The entrance should be at least 50’ long and include a wide turning radius. All traffic must use a stabilized entrance, and the entrance should be built to accommodate the largest vehicles accessing the site.
The use of aggregate is a traditional method to stabilize ingress and egress locations at construction sites. As mud and sediment build up in the aggregate, less sediment is removed by passing vehicle tires. The effectiveness of a traditional rock-tracking pad largely depends on the refresh frequency and the additional top dressing applied over the stabilized entrance. For projects involving excavation, wet conditions, or soil containing clay, resident engineers (RE) will often spec a combination of trackout solutions, including an aggregate tracking pad with a wheel wash or manufactured solution.
FODS Reusable Construction Entrance Mats
FODS introduces a modern, effective solution for trackout control that is both low-maintenance and environmentally friendly. Mats are designed to be installed as a standalone stabilized construction entrance and can be placed directly on unexcavated soil, concrete, or asphalt. Installation can be completed in as little as 30 minutes. Passing vehicle tires are deformed by the pyramids, opening the lugs and allowing sediment to fall onto the mats. When sediment fills the voids between the pyramids, a street sweeper or shovel is used to easily clean the mats to restore operation.
The design of FODS mats allows contractors to easily refresh their construction entrance after heavy traffic and adverse weather. Because FODS construction entrance mats are reusable, they can be moved to new locations for each phase of the project or subsequent projects. The low maintenance costs and a 10+ year expected service life provide an industry-leading Total Cost of Ownership.
Risks of Vehicle Trackout On Roadways
Safety is always a concern when it comes to trackout on active roadways. Traditional aggregate solutions pose the risk of rocks and debris entering the roadway or becoming lodged between tires or inside of tire lugs. Aggregate and sediment tracked onto roadways pose a risk to drivers, flaggers, and vehicles. In addition, trapped rocks and debris can be expelled at high velocities after the vehicle enters the roadway. The Caltrans Field Manual mentions the risk of larger vehicles tracking aggregate material and recommends larger aggregate to mitigate this risk.
The FODS Trackout Control System uses a rockless technique to clean vehicle tires and does not pose the same risk of injury or liability as aggregate-based construction entrances. FODS mats are effective at minimizing sediment trackout from vehicles of all sizes without introducing additional aggregate into the roadway.
Each FODS mat is fully recyclable and reduces the environmental impact from aggregate production, transportation, and disposal.
Contact us to find out more about using FODS Reusable Construction Entrances in California.
Resources
Caltrans Stormwater Pollution Control
Caltrans Construction Site Best Management Practices (BMP) Manual - Section 6
Caltrans Construction Site Best Management Practices (BMP) Manual
Caltrans Construction Site Best Management Practice (BMP) Field Manual and Troubleshooting Guide

