Imagine the Gotthard with no traffic jam. It's 18.4 km of twin-tube motorway under a fictional Alpine massif: one tube for each direction, three lanes each, lit end to end. The tunnel climbs to a crest 8.3 km in, winds through two long S-bends, and ends on 4 km of dead straight road. There the daylight at the far end starts as a dot and slowly grows.

The tube

• White enamel wall panels, a continuous LED light strip and a lamp over the road every 40 m, with brighter threshold lighting at both portals

• Recessed, lit SOS niches every 150 m, cross-passage doors every 300 m and a lay-by every 900 m

• Exit signs every 25 m, blue distance LEDs, jet fans, lane-signal gantries with message boards, and colour bands with a big number at every kilometre

• Three blue-lit rock caverns at 4.6, 9.2 and 13.8 km, wide enough to stop in

• Real darkness inside, like the stock game's own tunnels

Your tunnel, your light

12 lighting presets for the whole tube: LED white, warm white, sodium orange, cool white, blue, green, turquoise, violet, pink, red, a rainbow along the tunnel and a running rainbow. The lamps and the walls' own glow change together, and the game remembers your choice.

The run is timed

Drive into a portal and a clock starts ahead of your car. At the other end you get your time, average and top speed, plus what the Swiss average-speed cameras would make of it, from keine Busse all the way to Raserdelikt. You can switch the clock off in the menu if you just want to cruise.

Outside

There's a valley at each end with a river, a torrent crossed on bridges, and an electrified railway running into its own portal, with a train waiting at each end. You'll also find a cable car, farmsteads, snowy peaks with bare rock ribs, and around 30,000 trees and 79,000 clumps of real 3D grass along the roads. Before each portal there's the approach of a real Alpine crossing: metering signals, a control station with a lit canopy, and section-control cameras. Turning loops at both ends make the whole map one continuous circuit.

Features

• AI traffic supported: one-way three-lane tubes, right-hand traffic, tuned to motorway pace

• 6 spawn points, including one on the final straight with the light at the end of the tunnel

• A day lasts 2 hours of real time and starts at 10:00; street lights switch on at dusk

• Textures ship pre-cooked, so there's no long "importing textures" wait on first load

Controls

• E → Freeroam → Schwarzhorn-Tunnel: lighting colour and timer display on/off

• K / Shift+K: next / previous lighting colour