The speed limit for trucks are usually 10 km/h lower. In non-traffic jam conditions, a vehicle must travel at least 60 km/h (37 mph). Speed limits are enforced through radar activated cameras that take pictures of speed-violating cars. Because of protests, yellow warning signs are given in advance in Chinese of approaching radar activated cameras. As tailgating poses serious hazards of rear-ending, Article 6 of the Freeway and Expressway Traffic Control Regulation () requires the following minimum following distances when the weather is fine:  Longer following distance is required in the Hsuehshan Tunnel. In the tunnel portions of freeways, lane change is prohibited when the lane divider consists of two parallel solid lines, used when lane change is considered unsafe should a collision cause a vehicular fire. Headlights must be turned on when traveling through tunnels; this is enforced by special cameras. Unlawful lane change or failure to turn on headlights in a tunnel is subject to an administrative fine of 3000 new Taiwan dollars. Additional restrictions apply for the Hsuehshan Tunnel on Freeway No. 5, which is the longest tunnel in the entire system. Article 19 of the Freeway and Expressway Traffic Control Regulation prohibits uses of and entries onto the freeways by:  Odd-numbered freeways have tolls, which are automatically collected by ETC. The current rate for cars is (NT$1.2/km up to 200 km) + (NT$0.9/excess km), km being kilometers traveled per day. The first 20 km per day is free and thus deducted from the distance. Freeways may be used directly, but users are advised to apply for an “eTag”, which is free and when equipped gives 10% discounts and allows you to store pre-paid money for tolls. The eTag can also be set to pay tolls automatically with credit card or a savings account. Users without the eTag pay tolls at convenience stores 3 days after usage and if not, bills will be mailed to car owners. Freeway service and rest areas start appearing south of Taoyuan City on the No. 1 and No. 3 freeways. Most rest areas provide gas stations, gift shops, convenience stores, and food courts. The Qingshui rest area located on the 172.4 km mileage marker of National Highway No. 3 is so popular that visitors can only park for 45 minutes and are prohibited from barbecuing.