The Q4 e-tron’s pre-crash front seatbelts will tighten automatically in the event the vehicle detects an impending crash, improving protection against injury significantly. The Mustang Mach-E doesn’t offer pre-crash pretensioners.
Both the Q4 e-tron and the Mustang Mach-E have standard driver and passenger frontal airbags, front and rear side-impact airbags, side-impact head airbags, front seatbelt pretensioners, height adjustable front shoulder belts, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, post-collision automatic braking systems, daytime running lights, lane departure warning systems, blind spot warning systems, rearview cameras, rear cross-path warning and available around view monitors.
Side impacts caused 23% of all road fatalities in 2018, down from 29% in 2003, when the Insurance Institute for Highway Safety introduced its side barrier test. In order to continue improving vehicle safety, the IIHS has started using a more severe side impact test: 37 MPH (up from 31 MPH), with a 4180-pound barrier (up from 3300 pounds). The results of this newly developed test demonstrates that the Audi Q4 e-tron is safer than the Mustang Mach-E:
| 
 | Q4 e-tron | Mustang Mach-E | 
| Overall Evaluation | GOOD | GOOD | 
| Structure | GOOD | ACCEPTABLE | 
| 
 | Driver Injury Measures | |
| Head/Neck | GOOD | GOOD | 
| Head Injury Criterion | 41 | 115 | 
| Neck Tension | 178 lbs. | 357 lbs. | 
| Neck Compression | 22 lbs. | 45 lbs. | 
| Torso | GOOD | ACCEPTABLE | 
| Shoulder Deflection | .98 in | 1.42 in | 
| Shoulder Force | 178 lbs. | 268 lbs. | 
| Torso Max Deflection | .83 in | 1.42 in | 
| Torso Deflection Rate | 4 MPH | 9 MPH | 
| Pelvis | GOOD | GOOD | 
| Pelvis Force | 357 lbs. | 825 lbs. | 
| Head Protection | GOOD | GOOD | 
| 
 | Passenger Injury Measures | |
| Head/Neck | GOOD | GOOD | 
| Neck Tension | 67 lbs. | 112 lbs. | 
| Torso | GOOD | GOOD | 
| Shoulder Deflection | .28 in | .87 in | 
| Shoulder Force | 112 lbs. | 268 lbs. | 
| Torso Max Deflection | .71 in | .94 in | 
| Pelvis | GOOD | GOOD | 
| Pelvis Force | 446 lbs. | 535 lbs. | 
| Head Protection | GOOD | GOOD | 

