Gridlock is a free road-building traffic game you can play in your browser with a mouse or a finger. The city is a 12 by 12 grid. Small coloured squares are houses and each one owns a single car; large 2×2 blocks are destinations of the same colours. Drag across the grid to lay road tiles, and as soon as a house is connected to a matching destination its car sets off, delivers, and drives home again. Every completed delivery counts as one trip, and trips are your score. Destinations build up demand pips over time; when all six pips are lit an overflow ring begins to drain, and if it runs out the city is gridlocked and the game ends.
Road is scarce. You start with 18 tiles and receive 8 more at the start of every in-game week, so every tile has to earn its place. Strategy matters more than speed: keep the centre of the map clear so new buildings have room to connect, and prefer short loops between a house and its destination over long arteries that every car has to share, because only two cars fit in a cell and a jam anywhere backs up everything behind it. Erase dead ends to recover tiles, and reroute rather than extend when a new building lands in an awkward spot. The Daily mode gives everyone the same seeded city with one attempt per day, so you can compare scores with friends; Practice mode is unlimited and tracks your best.