Highlighting path or route-Urgent

I am an engineering student and I ought to display a map for my major project displaying some information. The information I would be displaying will be the congestion state of the road section based on the video footage retrieved from the surveillance camera installed. The problem I have been encountering is to be unable to find suitable method to highlight a section of road (provided the longitude and latitude of endpoints of section of path or road). Each time If I attempt to draw line to highlight the road, It draws a straight line. So is there any way to trace a section of road by providing endpoint LonLat coordinates and highlight them?

Thanks in advance.