I'm also intrigued by the potential planning and design implications of CAVs over time. Of course we are still designing on the basis of conventionally driven vehicles of all shapes and sizes, but I could see new roads or dedicated "managed" lanes being limited to CAV use in the not-too-distant future. Of course, ultimately, it appears likely that all automotive travel will be in CAVs.
In my mind, a CAV-focused road (non-CAVs excluded) could involve things like:
- narrow lanes, because vehicles are "on a wire"
- one lane per direction only, since "nose to tail" operation would provide more vehicular capacity than any four-lane conventional road
- hard surface only in the tire tracks, again because vehicles will be tracking very specifically and not wandering or crossing lanes
- the space between tire tracks could be "green" or used for water infiltration / drainage (or potentially even flat solar panels)
- no shoulders, since breakdowns are few and far between and there is no risk of an automated vehicle smashing into a slow or stopped CAV
- limited to no road signage, since wayfinding and directions are built in to the CAV guidance systems
- no traffic signals, since an automated system could slot each approaching vehicle through a conflict zone in the most efficient manner with no risk of collision
- physically separated cycling facilities, since all of the above doesn't work if bikes etc are mixed in with CAV traffic
- pedestrian crossings might be allowed everywhere (since CAVs are programmed to avoid hitting pedestrians) or might be at controlled locations or grade separated; we still have to see how the interaction between CAVs and peds works out
- a physical (gate) or electronic barrier to prevent non-CAVs from accessing or using the route
- no speed limits, since there is no safety-related need (assuming the pedestrian question is resolved), so operating speed could be based on physics alone (i.e. steep grades, banking, etc.)
- smooth pavement to reduce noise (but retaining enough grit to be effective in braking and accelerating zones); tire track slabs could be prefabricated so as to maximize consistency and quality control
- heated pavement slabs to eliminate issues of snow and ice on the wheel tracks
- little road lighting, since the "driver" doesn't need to see where they are going in an automated system
- potential use of slim / transparent noise barriers or treatments, to minimize impact of wind and tire noise in high-speed retrofitted corridors
- likely use of roundabouts for the most efficient means of moving vehicles on and off a CAV route.
- specialized maintenance vehicles and practices
Overall, a CAV road with these design parameters could be created as a narrow, sinuous corridor with relatively low impact on its surroundings - far less than the equivalent "conventional" roadway in any case. It would be interesting to compare both costs and cost-effectiveness; I suspect a CAV road would net out at a lower cost per km than the equivalent conventional (current) design. These reductions might allow reconsideration of needed road corridors that have been rejected in the past on the basis of the scale, cost, and impact.
Amazingly, even though CAVs are coming in the next couple of decades, we are currently not planning or designing for any of this related infrastructure (not even as a pilot project). Rather than taking advantage of the CAV direction, the roads and highways (and transitways) we are currently investing in will last for a century or more, and our current approach commits us to this over-designed, inefficient, highly impactful infrastructure (and all of the city / development that surrounds it).
The parameters you describe are all feasible, but the status quo will not brook challenge until the technology is more mature, I'm afraid. At least there _are_ pilots happening in parts of the world: Cavnue is doing one in Michigan (and I think Texas) and the government of Japan is, I understand, looking into an AV-only highway connecting Toyko and Osaka.
I'm also intrigued by the potential planning and design implications of CAVs over time. Of course we are still designing on the basis of conventionally driven vehicles of all shapes and sizes, but I could see new roads or dedicated "managed" lanes being limited to CAV use in the not-too-distant future. Of course, ultimately, it appears likely that all automotive travel will be in CAVs.
In my mind, a CAV-focused road (non-CAVs excluded) could involve things like:
- narrow lanes, because vehicles are "on a wire"
- one lane per direction only, since "nose to tail" operation would provide more vehicular capacity than any four-lane conventional road
- hard surface only in the tire tracks, again because vehicles will be tracking very specifically and not wandering or crossing lanes
- the space between tire tracks could be "green" or used for water infiltration / drainage (or potentially even flat solar panels)
- no shoulders, since breakdowns are few and far between and there is no risk of an automated vehicle smashing into a slow or stopped CAV
- limited to no road signage, since wayfinding and directions are built in to the CAV guidance systems
- no traffic signals, since an automated system could slot each approaching vehicle through a conflict zone in the most efficient manner with no risk of collision
- physically separated cycling facilities, since all of the above doesn't work if bikes etc are mixed in with CAV traffic
- pedestrian crossings might be allowed everywhere (since CAVs are programmed to avoid hitting pedestrians) or might be at controlled locations or grade separated; we still have to see how the interaction between CAVs and peds works out
- a physical (gate) or electronic barrier to prevent non-CAVs from accessing or using the route
- no speed limits, since there is no safety-related need (assuming the pedestrian question is resolved), so operating speed could be based on physics alone (i.e. steep grades, banking, etc.)
- smooth pavement to reduce noise (but retaining enough grit to be effective in braking and accelerating zones); tire track slabs could be prefabricated so as to maximize consistency and quality control
- heated pavement slabs to eliminate issues of snow and ice on the wheel tracks
- little road lighting, since the "driver" doesn't need to see where they are going in an automated system
- potential use of slim / transparent noise barriers or treatments, to minimize impact of wind and tire noise in high-speed retrofitted corridors
- likely use of roundabouts for the most efficient means of moving vehicles on and off a CAV route.
- specialized maintenance vehicles and practices
Overall, a CAV road with these design parameters could be created as a narrow, sinuous corridor with relatively low impact on its surroundings - far less than the equivalent "conventional" roadway in any case. It would be interesting to compare both costs and cost-effectiveness; I suspect a CAV road would net out at a lower cost per km than the equivalent conventional (current) design. These reductions might allow reconsideration of needed road corridors that have been rejected in the past on the basis of the scale, cost, and impact.
Amazingly, even though CAVs are coming in the next couple of decades, we are currently not planning or designing for any of this related infrastructure (not even as a pilot project). Rather than taking advantage of the CAV direction, the roads and highways (and transitways) we are currently investing in will last for a century or more, and our current approach commits us to this over-designed, inefficient, highly impactful infrastructure (and all of the city / development that surrounds it).
The parameters you describe are all feasible, but the status quo will not brook challenge until the technology is more mature, I'm afraid. At least there _are_ pilots happening in parts of the world: Cavnue is doing one in Michigan (and I think Texas) and the government of Japan is, I understand, looking into an AV-only highway connecting Toyko and Osaka.