Abstract: Example embodiments relate to modular luminaire assemblies for tunnels. One example luminaire assembly includes a plurality of interconnectable modules. The plurality of interconnectable modules includes at least an electronic module and at least a first optical module. The first optical module include at least one printed circuit board that includes at least one corresponding LED array and at least one corresponding optical plate. The electronic module includes driver circuitry for driving the at least one LED array of the at least one printed circuit board. The first optical module includes a tray containing the printed circuit board and the optical plate, and an at least partially light transmitting cover closing the tray. The tray has a bottom face and a first edge between the cover and the bottom face. The electronic module includes a tray containing the driver circuitry and a cover closing the tray.