For enhanced safety, the front seat shoulder belts of the Audi A5 are height-adjustable to accommodate a wide variety of driver and passenger heights. A better fit can prevent injuries and the increased comfort also encourages passengers to buckle up. The Mercedes CLA doesn’t offer height-adjustable seat belts.
Both the A5 and CLA have child safety locks to prevent children from opening the rear doors. The A5 has power child safety locks, allowing the driver to activate and deactivate them from the driver's seat and to know when they're engaged. The CLA’s child locks have to be individually engaged at each rear door with a manual switch. The driver can’t know the status of the locks without opening the doors and checking them.
In the past twenty years hundreds of infants and young children have died after being left in vehicles, usually by accident. When turning the vehicle off, drivers of the A5 are reminded to check the back seat if they opened the rear door before starting out. The CLA doesn’t offer a back seat reminder.
The A5 has a standard front seat center airbag, which deploys between the driver and front passenger, protecting them from injuries caused by striking each other in serious side impacts. The CLA doesn’t offer front seat center airbags.
In a Vehicle-to-Vehicle Frontal Crash Prevention 2.0 test conducted by the Insurance Institute for Highway Safety (IIHS), the Audi A5 achieved a “Good” rating - the highest possible - for its performance in forward collision warning and automatic braking systems, demonstrating its excellent capabilities in preventing collisions. The Mercedes CLA has not been tested.
The A5 has a standard Secondary Collision Brake Assist, which automatically applies the brakes in the event of a crash to help prevent secondary collisions and prevent further injuries. The CLA doesn’t offer a post collision braking system: in the event of a collision that triggers the airbags, more collisions are possible without the protection of airbags that may have already deployed.
Over 200 people are killed each year when backed over by motor vehicles. The A5 has standard Maneuver Assist that uses rear sensors to monitor for objects to the rear and automatically applies the brakes to prevent a collision. The CLA doesn’t offer automatic braking for stationary objects directly to the rear.
To provide maximum traction and stability on all roads, All-Wheel Drive is standard on the A5. But it costs extra on the CLA.
Earlier warning of stopped traffic, traffic signals, dangerous road conditions, weather, or accidents, can keep driver's safer and prevent crashes. The A5 has Car-to-X Services, a system that seamlessly communicates important warnings to the driver about impending danger, if they're available. The CLA doesn’t offer a system that can receive automated systems from infrastructure.
The A5’s standard lane departure warning system alerts a temporarily inattentive driver when the vehicle begins to leave its lane and gently nudges the vehicle back towards its lane. A lane departure warning system costs extra on the CLA.
Both the A5 and the CLA have standard driver and passenger frontal airbags, front side-impact airbags, driver and front passenger knee airbags, side-impact head airbags, front seatbelt pretensioners, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, blind spot warning systems, rearview cameras, rear cross-path warning and driver alert monitors.
The Audi A5 weighs 474 to 596 pounds more than the Mercedes CLA. The NHTSA advises that heavier cars are much safer in collisions than their significantly lighter counterparts.
The Audi A5 has achieved the Insurance Institute for Highway Safety’s (IIHS) highest rating of “Top Safety Pick Plus” for the 2025 model year. This distinction is based on its exceptional performance in IIHS’ rigorous battery of safety tests. Specifically, it earned a “Good” rating in the latest, more stringent moderate overlap front crash test, a “Good” result in the updated side impact test, and a “Good” score in the revised pedestrian crash prevention test. The CLA has not yet been evaluated by the IIHS for 2025.