Transport vibration levels in trucks were measured as a function of truck speed, road conditions and load level. The trucks consisted of one normally loaded truck and one overloaded truck with leaf-spring suspensions. Truck speeds were divided into three groups: 0-30 km/h, 31-60 km/h and 61-90 km/h. Traffic roads consisted of highways, arterial roads (ARs), secondary roads (SRs) and tertiary roads (TRs). The results revealed that transport vibration levels increased with truck speed; TRs contributed to the highest transport vibration levels, followed by SRs, ARs and highways. The power spectral density peaks were at 3 or 3.5 Hz. Overloading probably suppressed transport vibration levels especially at low speeds.