The Tesla Model S and BMW i3 electric vehicles have missed out on being considered a Top Safety Pick by the US's Insurance Institute for Highway Safety (IIHS).
In order to qualify as a 'Top Safety Pick', vehicles need to earn 'Good' ratings in all five crash tests - small overlap front, moderate overlap front, side, roof strength, and head restraints - along with having a crash prevention system that earns an 'advanced' or 'superior' rating.
Additionally, vehicles can be awarded a 'plus' if they meet all those criteria and come with good or acceptable headlights.
The Model S achieved good ratings in four of the five tests, only achieving an acceptable rating for the small overlap front crash tests, due to the front seat belt allowing the dummy to move too far forward, its head contacting the steering wheel through the airbag.
Measurements from the dummy indicated head and lower right leg injuries would be possible in a real-world scenario.
The ratings for the Model S apply to 2016 and 2017 model-year vehicles produced after October 2016.
In response to the seat belt issue, Tesla says it made modifications to production on January 23 to address the head-contact problem raised by the crash test - the IIHS will crash test the updated Model S as soon as it can be delivered.
One Model S variant, the top-spec 100D, also fell short in the roof strength test as a result of the extra weight from the bigger battery pack - a potential concern in the event of a rollover crash.
The IIHS says the strength-to-weight ratio means the Model S 100D only earns an 'Acceptable' rating.
Despite coming with automatic braking equipment as standard, not all US versions of the Model S have the system activated, meaning the Tesla also cannot be rated for front crash prevention. Additionally the IIHS rated the Model S's headlights as 'Poor'.
Meanwhile, the BMW i3 also misses out on a Top Safety Pick title, due to its 'Acceptable' rating in the head restraint and seat evaluation - measuring a vehicle's ability to protect against neck injuries in a rear crash.
The i3 also scored an advanced rating for its optional front crash prevention system, while its headlights were deemed 'acceptable'.
David Zuby, executive vice president of the IIHS and chief research officer, said: "There's no reason the most efficient vehicles can't also be among the safest".
"We hope Tesla and BMW will continue to refine the designs of their electric models to maximize driver protection and, especially in the case of Tesla, improve their headlights."
"Among small cars, the i3 is the only 2017 model that doesn't earn a good rating," he added.
The Chevrolet Volt (a new version of the car previously sold here as the Holden Volt) and Toyota Prius Prime (a plug-in variant not offered here) were awarded the 'Top Safety Pick+' rating thanks to their 'Good' results across all five crash tests, 'Good' and 'Acceptable' headlights respectively, along with 'Superior' front crash prevention systems.