Selenium Tests: In about 1/10th of tests: Chrome failed to start: exited abnormally




I am running quite some Selenium tests via PHPUnit, in total 18 test classes. Each test class starts its own browser instance.
While locally I never get an error, about every 10th time on circleCI Chrome does not start with the following error:

> UnknownServerException: unknown error: Chrome failed to start: exited abnormally
>   (unknown error: DevToolsActivePort file doesn't exist)
>   (The process started from chrome location /usr/bin/google-chrome is no longer running, so ChromeDriver is assuming that Chrome has crashed.)
>   (Driver info: chromedriver=2.43.600233 (523efee95e3d68b8719b3a1c83051aa63aa6b10d),platform=Linux 4.4.0-139-generic x86_64) (WARNING: The server did not provide any stacktrace information)
> Command duration or timeout: 109 milliseconds
> Build info: version: '3.14.0', revision: 'aacccce0', time: '2018-08-02T20:13:22.693Z'
> System info: host: '37665e1ca470', ip: '', 'Linux', os.arch: 'amd64', os.version: '4.4.0-139-generic', java.version: '1.8.0_181'
> Driver info: driver.version: unknown

Of course this is breaking my tests, causing me to re-run about every second workflow until it succeeds.
Any hints how to fix this?