Overall efficiency recorded on a 140 mile round trip with both cars starting with a full battery. The Clarity followed the Volt at 2.7 seconds using it's ACC and the route contained back roads and interstate with speeds ranging from 50 to 75 MPH. I reset Trip A on the Clarity and Trip B on the Volt as well as used the Volt's energy consumption display for this comparison.
- Volt EPA: 53 AER/40 MPG Combined: Actual trip results: 140 MPGe on battery; 48 MPG on gas, 92.1 MPG combined overall.
- Clarity EPA: 47 AER/42 MPG Combined: Actual trip results: MPGe on battery unknown (the car doesn't report this); 54 MPG on gas, 95.5 MPG Combined overall.
The actual trip results confirm the Clarity is just slightly more efficient than the Volt. Over the long haul (Denver to New Hampshire and back which my wife and I do each year) I expect the Clarity to use 5 to 10 gallons less gasoline. The Volt's larger battery and gas tank gives it an edge in range, but not one that's significant.
The Clarity is larger and more comfortable to ride in. However, it's not a driver's car and doesn't have the instant response to the throttle that I've become accustomed to in my Volt. The Volt isn't a driver's car either except in comparison to the Clarity. In HV mode punching the throttle results in the Volt jumping forward by using the electric motors. The Clarity, even in sport mode, feels sluggish by comparison. The Clarity responds better in EV mode, but this gives the car a dual personality depending on the mode. The Volt has one driving personality because it taps a roughly 0.4KWh buffer held in reserve even when "fully depleted." While both cars have regenerative and blended braking the Volt's regenerative braking is much more aggressive via the regenerative braking paddle or by shifting to L. Coming from the Volt I find the Clarity's regen paddle to be useless, even on max regen. On the flip side I find the Clarity's coast to be very similar to the coast in my previous 2012 Chevy Cruze ECO Manual in 6th gear, which I'm sure is part of how the Clarity achieves the EPA and real world efficiency numbers it does.
The Volt tells you anytime it will be running on ICE for engine maintenance mode (EMM), engine running do to temperature (ERDTT), or fuel maintenance mode (FMM). EMM runs after six weeks of no ICE usage to lubricate and check the ICE engine. FMM runs whenever the average age of the gasoline in the tank reaches 360 days and will run the ICE until you either run out of gas or you put at least three gallons of gas into the tank. ERDTT runs whenever the temperature falls below 32F, but each driver can defer this to either 15 or -15F depending on the model year. This is all documented in the Volt owners manual. I suspect the Clarity will do similar engine, fuel, and temperature related operations but it's not documented in the owners manual.
Cargo space definitely goes to the Volt. The Clarity's trunk is a joke in comparison - this is the big difference between any hatchback and sedan.
Creature features go to the Clarity. It's wider, with wider seats and more space between them. In addition, while the Volt is a "five" passenger car, the Clarity is a five passenger car. Besides being wider, the Clarity's traction battery is entirely under the rear seats as opposed to the Volt's traction battery, which is a T shape that gives the interior of the car a hump similar to that of a rear wheel drive car's drive shaft. The Clarity has dual zone temperature control. My Volt doesn't have ACC or LKAS so I can't compare these features between the cars. I am impressed with the Clarity's systems however.
The Volt has an available spare tire. This is probably the single biggest weakness of the Clarity. As at least one member here has discovered, it can take hours even in major cities to get a tow truck. I personally have waited over an hour for a tow truck in Denver. Before we take our Clarity on a long road trip I'll have to figure out how to acquire a spare tire and jack for the car. On every single trip I've taken to New Hampshire and back I've seen at least one car on the side of the road in each state with a flat tire - having a spare tire is simply good preparation for any road trip.
The 2019 Volt has an optional 7.2KWh charger; my Volt has a 3.6KWh charger; the Clarity has a 6.6KWh charger. From a charging standpoint our Clarity and Volt are a tie. However, if I were to pay for charging the Clarity would be the better car simply because most pay charging stations charge by the hour and not the KW consumed. Both cars will refuel quickly on a road trip and both have sufficient range on gas to drive them cross country without waiting for the batteries to recharge.
Bottom line - I grew up in and learned to drive manual transmission sports cars. The Volt is the better car for me. The Clarity on the other hand, is much better for my wife, who has never driven sports cars. The Clarity will also be our road trip car once I resolve the spare tire issue.
The Clarity has one other really big advantage over the Volt - Honda is still selling it, unlike GM cancelling the Volt.