Rumble strips could reduce road accidents
Room could be made for emergency vehicles during traffic
Undersea tunnels could have sculptures and light effects
Wildlife corridors could encourage biodiversity and conservation
Highways could be like roller coasters
Highways/roads could be solar powered
Wildlife bridges / tunnels could save animals and people
Cafe, toll, and fast food drive-through patrons could pay-it-forward
Tunnels could ease traffic, be weatherproof, and be resistant to earthquakes
Ramp meters could be used to decrease traffic congestion and improve safety
Adaptive cruise control could reduce congestion, travel time, and traffic