I procrastinated for an hour and did some quick research to see how much the drag coefficient and rolling resistance affect fuel economy:

https://www.nap.edu/read/11620/chapter/5#39

Specifically a) city (top) and b) highway (bottom):

https://www.nap.edu/openbook/0309094216/xhtml/images/p2000f6...

For an internal combustion, midsize passenger car, including standby, here are the losses:

City:

Engine + driveline + standby: 85%
Aero: 3%
Rolling: 4%
Braking: 6%
Accessories: 2%
---
100%

Highway:

Engine + driveline + standby: 78%
Aero: 11%
Rolling: 7%
Braking: 2%
Accessories: 2%
---
100%

Looks like Tesla motors are 93-97% efficient:

https://www.pcmag.com/news/report-tesla-model-sx-upgrading-t...

And regenerative braking is 80% * 80% = 64% efficient, or 36% costly (about 1/3 as much energy wasted):

https://www.tesla.com/blog/magic-tesla-roadster-regenerative...

I'll just run the math for an electric car with a 95% efficient electric motor, assuming 0% driveline losses with direct drive and no transmission, with no standby losses:

City:

Engine + driveline + standby: 5%
Aero: 3%
Rolling: 4%
Braking: 2%
Accessories: 2%
---
16% (already 6.25 times more efficient by going electric)

Highway:

Engine + driveline + standby: 5%
Aero: 11%
Rolling: 7%
Braking: 1%
Accessories: 2%
---
26% (already 3.85 times more efficient by going electric)

Rescaled to 100% by multiplying each term by (100/total):

City:

Engine + driveline + standby: 31%
Aero: 19%
Rolling: 25%
Braking: 13%
Accessories: 12% (rounded down to make 100% total)
---
100%

Highway:

Engine + driveline + standby: 19%
Aero: 42%
Rolling: 27%
Braking: 4%
Accessories: 8%
---
100%

So we can see that city driving is dominated by engine efficiency and highway driving is dominated by aerodynamic efficiency. But both lose about 25% (1/4 of the energy!) to rolling resistance.

Googling "mileage loss percentage due to drag coefficient" and "mileage loss percentage due to rolling resistance":

http://www.arcindy.com/effect-of-aerodynamic-drag-on-fuel-ec...

For passenger cars this means that aerodynamics is responsible for a much higher proportion of the fuel used in the highway cycle than the city cycle: 50% for highway; versus 20% for city. This means that if you make a 10% reduction in aerodynamic drag your highway fuel economy will improve by approximately 5%, and your city fuel economy by approximately 2%.

https://www.nhtsa.gov/DOT/NHTSA/NVS/Vehicle%20Research%20&%2...

A 10 percent decrease in tire rolling resistance resulted in an approximately 1.1-percent increase in fuel economy for the vehicle. This result was within the range predicted by technical literature.

Converting these for electric in city and highway by multiplying by 6.25 and 3.85 respectively:

City:

Each 10% reduction in aerodynamic drag increases mileage by 13%
Each 10% reduction in rolling resistance increases mileage by 7%

Highway:

Each 10% reduction in aerodynamic drag increases mileage by 31%
Each 10% reduction in rolling resistance increases mileage by 4%

Comparing drag coeficents:

https://en.wikipedia.org/wiki/Automobile_drag_coefficient#Ty...

Lucid Air: 0.21
Tesla Roadster: 0.35
Tesla Model S: 0.24
Tesla Model 3: 0.23
Tesla Model X: 0.25

So the Lucid Air has about a 10% better drag coefficient than the Tesla model 3, which gives it (at most) 13-31% better range city-highway. I think this is a liberal estimate, and that drag coefficients will never be below about 0.20, so improvements here will probably be marginal from here on out.

It seems to me that a better return on investment might be to fix tires. Someone needs to think outside the box on this and create a tire that acts stiff at high speed, but still grips while cornering and braking. Eliminating this resistance would add 100 miles to electric car range.

I ran this math from a first order perspective, to give an idea of relative costs. I'm sure it's off (since drag is nonlinear), but it helps visualize where the energy goes. Seeing that accessories use as much or more energy than regenerative braking was eye-opening for me.

Oh and you don't even want to know about bicycles. The upright position is the worst possible, and wastes most of the rider's energy. I wish recumbants were safer and more affordable, although this matters less each year with improvements in electric assist, mostly from reduced cost and better batteries.