Lighting for Transit

Technical problem-solving in service of humanistic design

About lighting for transit

Roadway, tunnel, and transit projects are often described as ‘functional’ or ‘utilitarian,’ but I think it’s important to remember that these facilities will be used by humans.

They do typically have a lot of technical constraints, with detailed lighting criteria, a desire to reduce energy and maintenance costs, and often challenging mounting conditions, but meeting these challenges while improving lighting quality for the end user is rewarding work.

Rose Pak Station

Rose Pak station is the terminus of the new SFMTA Central line. The lighting mounting conditions are challenging, with multiple height spaces directly adjacent to each other and limited accessibility. We wanted the lighting to feel open, a pleasant surprise for visitors to the 100′ deep station.

Above, study for platform lighting and final result. Right, study of comparative light levels throughout the station and a photo of the 100′ deep main concourse.

Above, train tunnel lighting study for SFMTA (Muni), to study visual performance of various options for subway train operators. Right, luminance calculation for Yerba Buena Island tunnel to analyze required luminances for drivers entering the tunnel. Below, rendering of proposed subway platform lighting.

Tunnel lighting design

Tunnels can be particularly challenging for lighting design. Vehicular usage requires quick reactions based on accurate visual information, but the human eye has limitations for adaptation time, glare, and uniformity. Experience is helpful for integrating all these complex criteria (and energy usage, and maintenance), but the solution for each tunnel is unique.

SFMTA LED Upgrades

Prior to retrofitting to LED, each SFMTA subway platform had about 400 32W fluorescent lamps. The energy density was 1.4W/sqft. In addition, as the lamps accumulate soot from the overhead electrical cables they must be rotated halfway through their life. An LED retrofit reduce the power density by 60%, saving about $7500 per platform from electricity bills alone.