Trench drain systems for highway use need to be approved by the Department of Transportation of the local State. The approved products from state to state are similar and have a few similar properties.
Think about this:
- High Strength Grating. Class D load requirements are a standard specification. Government projects will need to meet AASHTO or DIN load standards.
- Open Area. The more open space which a grate has, the more water that drain can handle until the channel physically reaches its capacity.
- High flow capacity. The first criteria in designing a trench drain system is to determine what capacity is required to handle a large storm. For large watershed surfaces, large capacity drains are required.
- Cleaning. Bolt-down systems increase a trench drain's strength but also make maintenance harder. If possible, choose a drain that offers cleanout sections.
Where to find Roadway Trench Drains:
- Toll booths
- Weigh stations
- Tunnel entrances / exits
- Roadside shoulders
Roadway trench drain can be used to cross a road to keep run-off water from entering another section of the road (such as a toll booths and weigh stations). However, a large percentage of trench drains that are installed in roadways are running parallel to the direction of traffic.
When the road is flat and provides little natural drainage slope, trench drains are used in the median and shoulder areas.
Recommendations for High Volume Road Drainage Systems
Polycast 900 (by Hubbell)
The Polycast 6" 900 Series features a non-removable frame and grate that exceed AASHTO highway standards for high load rating and prevent grates from shifting in place. With up to 470 GPM per outlet, the Polycast 900 handles water across long stretches of roadway. Polycast 900 complies with CALTRANS Section 10-1.35 and 75-1.02.
3000 Series by Trench Drain Systems
The 3000 Series is a high volume drainage system with an integral steel frame that reinforces the system. With four different slope options available, the 3000 Series can handle up to 3,000 GPM and up to 120 ft of continuous slope. Exceeds CALTRANS specifications. Meets AASHTO specifications for highway drainage and highway bridges.
EconoDrain #12 Pt-3 (by MultiDrain)
The 12" wide EconoDrain #12 PT-3 handles high volume water flow on well-traveled roads. With three locking points per grate, the EconoDrain #12 PT-3 is safe from tampering or shifting. Meets AASHTO M306 - H20 & H25 requirements as well as FAA AC 150 5320-6D.
Z888 Hi-Cap Slotted Drain (by Zurn)
Zurn's high capacity slotted drain system catches stormwater runoff across highways. Available in 12", 18" and 36" widths, Z888 Hi-Cap drains prevents water from building up on roadways and creating traffic hazards. FAA rated, and AASHTO H20 & H25 rated.