It is unclear to me what you are comparing with what
For both types, the most efficient energy use will be at a steady speed.
For both types, the resistance to motion is significantly worse at a higher speeds than when travelling slowly.
So for an electric motor, the most efficient travel will be at the slowest steady speed possible.
That would be true for combustion engines too, were it not for the fact that they need gears, and I determined (empirically) in my previous diesel car that its fuel consumption was best at the slowest speed it will go in top gear, which was about 40 mph. Any faster, and the fuel consumption increased. Any slower, and the gear shifted down, again increasing the fuel consumption.
With electric propulsion, for normal braking, the energy is reclaimed by reversing the flow of electricity so instead of the battery powering the motion, the motion powers the battery: "regenerative braking" (but you don't get back all
of the energy that was used to accelerate).
For a combustion powered vehicle, that energy is lost, wasted, dissipated as heat through the brakes.
So in slower speed urban driving, the electric vehicle has it for efficiency: it is more efficient both under power and
But on the open highway, there is less of a difference between the two types of engine, from the speed factor, and less braking too.
As for a hybrid vehicle: combustion and electric power. For short urban journeys under battery power, they do much better than purely combustion engines, for the reasons stated.
However, on the highway, they can't go far on the battery alone, so they have to burn fuel. Now, it is better to power the wheels directly, than to convert the energy to electricity, and drive the wheels with that, because no energy conversion process is 100% efficient.
So if your journeys are mainly on fast highways at a steady speed, there is little point having the more expensive hybrid technology.
The simple answer as to why an electric vehicle is more efficient in urban use than on the highway, is because there is considerably less resistance to motion at lower speeds. Regenerative braking doesn't affect that at steady speeds, but it reduces the energy wastage in stop-go running. The regenerative system can never recover 100% of the energy though, so I presume there must be a break-even point somewhere: repeated rapid acceleration to the urban speed limit alternated with sharp braking might reduce the efficiency so it's less than steady speed running on the highway.
It's the other way round with ICE vehicles, because in town they are working below their most efficient speed, as well as the unrecoverable losses due to stop-go running, and idling when stationary.