I asked THCEA to work with Figg to come up with generic cost estimates for elevated express lanes projects using this design approach. Assuming zero right of way costs but including design, construction management, and a contingency, the figures they gave me (based on today's materials costs) are $18 million per lane-mile for a two-lane facility, $15 million per lane-mile for a three-lane facility, and $13.6 million per lane-mile for a four-lane elevated facility. These figures apply to a modest-length facility in the 5-10 mile range. The per-mile cost would be lower for longer projects. Costs would be higher if there were a lot of on-ramps and off-ramps. But express lanes are intended for relatively long trips, not the kind of short on-and-off trips that clog up many of our freeways. So a lot fewer on- and off-ramps would be needed than for the freeway itself.. (Bold added)
Cost from above:
$18 million per lane-mile for a two-lane facility
$15 million per lane-mile for a three-lane facility
$13.6 million per lane-mile for a four-lane facility
An elevated expressway should cost under $14 million/lane-mile.