During the May Day holiday, Xiaoming and his family went to go on road trip. On the way, Xiao Ming noticed the traffic sign as shown in the figure, (1) is obeying the traffic.

(1) The traffic sign indicates that the driving speed does not exceed 40km/h and the distance is 18km from Shangqiao.

∫v = ST，

∴ The fastest time from the signboard to the bridge: t = SV =18km 40km/h = 0.45h = 27min.

(2) Xiao Ming's father needs to drive through the sign to get to the bridge: t'=30min=0.5h,

The average speed of the car is: V' = ST' =18km0.5h = 36km/h. 。

Answer: (1) It takes 27 minutes from the sign to the bridge, provided that the traffic rules are observed.

(2) If it takes 30 minutes for Xiaoming's father to drive through the distance shown in the sign, the average speed of the car is 36 km/h. 。