1,、道=lane, 里=inside 2. must riding on bike lane.

“里”is an adverb here. “里”在这里是一个副词。 FYI:“里”also can be an unit of distance. 1“里”=500m 1“公里”=1000m

Thanks so much

"道里" is not a word in this sentence.自行车道 is refer to a kind of road for riding bicycle bike only. 道里在这里不是一个词。“自行车道”指一种专门用来骑自行车的路。 The mean of the sentence is (somebody)should ride bike on the road(自行车道). 这句话的意思是：（骑自行车）一定要在自行车道骑。 Hope you can understand this.My poor English...