The goal of the bill is to give police a device that plugs into a phone and scans logs to see if a driver was texting or calling during the crash. And if drivers refuse to hand over their phones, they would lose their driver's license, under the proposed bill -- just as suspected drunk drivers are required to submit to breathalyzers.
Curious what cases you'd rely on for that proposition, because I'm more or less completely certain that it is dead wrong.
As the article itself notes, states already have laws that place you in the position of voluntarily agreeing to submit to a breathalyzer test OR to face automatic license suspension. These laws have been upheld as perfectly constitutional because to the extent it is a search, it is a consent search.
As for the 5th Amd., the Supreme Court has even held that it does not violate the 5th amendment to admit evidence in court that you refused the test, because they don't see blowing into a breathalyzer (or the refusal to do so) as being on par with being forced to provide incriminating testimony against yourself. (Contrast Massachusetts, where in 1992, the SJC held in Opinion of the Justices that evidence that you refused a breathalyzer is not admissible under the state constitution because it is the equivalent of testimonial evidence that the driver knows or suspects he has consumed enough alcohol to have committed OUI).
This would be the same thing, but for plugging the phone into a device to provide physical evidence that you were violating the law. With a breathalyzer, it's the percentage of alcohol in your blood stream. With this, it's whether a text function was active at a particular time.