When vehicles in multiple lanes encounter a reduction in lane capacity or heavy congestion ahead, how should drivers merge according to the Road Traffic Safety Law?

1. Merge alternately, one vehicle from each lane in turn (zipper merge / 交替通行)
2. Force your way through by following the car ahead with zero bumper gap
3. The larger vehicle always has priority over smaller passenger cars
4. Vehicles in the left lane always have continuous absolute right-of-way