maybe someone stole the stones from one side to another and dropped one in between without realizing the fact that it can cause great damage to road users. I have even seen burqa clad ladies crossing motorways by watching at left (when traffic is coming from right) and then after crossing watching at right (while traffic is coming from left) so for them the road is always empty, lol.
Glad you are o.k
BTW C drive is best for motorways, hard tread and soft walls, love the combo