FM 646 Reconstruction
Galveston County, Texas
The FM 646 project involves the reconstruction and upgrade of the existing roadway for Galveston County and TxDOT, totaling approximately 1.2 miles between FM 1764 and SH 6.
This project includes reconstructing the existing two-lane, asphalt roadway with open roadside
ditches to a new roadway with four traffic lanes, two-way left turn lane, and storm sewer. Roadway
improvements require purchasing an additional 20-feet of ROW. BBI coordinated with Galveston
County and TxDOT during the ROW acquisition process and proposed modifications to the proposed
ROW to minimize cost and impacts to adjacent landowners and businesses. The roadway realignment
met TxDOT’s design criteria and included a new 150-foot pre-stressed slab beam bridge over
Highlands Bayou. Changes were made to the roadway profile to meet TxDOT design criteria and
minimize the need for construction easements during construction, reducing the overall cost of the
project. The bridge design includes four lanes, a raised sidewalk, and a combination rail on the outside.
The bridge foundation design was performed using the CAP 18 program. The realignment required
keeping a portion of the existing roadway in place to maintain access to city streets and businesses.
Signal design included modification to the signal at the FM 1764 intersection and re-designing the signals at 6th Street and SH 6. The signal at SH 6 required coordination with the Union Pacific Railroad due to
its proximity to their railroad crossing. A Traffic Control Plan was created to ensure traffic flow would be minimally affected, and proper drainage would be maintained throughout construction. TxDOT expressed the concern about drainage due to the problems on an adjacent section of FM 646 currently under construction, so the construction was phased to ensure concerns were met.