Attempted several times. The last one:
Survived for - 2:45, Notifications cleared: 9
Two things I would say:
1) Balance so that the difficulty doesn't increase so fast
2) I think the game poorly conveys the message that you shouldn't text while driving:
a) In real life you "control" wheel in phone with different hands at the same time, in this game - you can't. While playing this game I have a sentiment, that I'd do much better if game allowed me to control a car with my left hand, say with AD keys
b) People don't typically go multitasking when they perform a nontrivial task already (which navigating in-game roads at such high speed is). The whole point of "don't multitask" is that people can't even focus on two simple tasks at the same time and even if driving alone feels boring, you shouldn't reach for a second task.
So I think the best would be to take make driving and texting two really simple (=infinitely playable without deaths) boring tasks and combine them in such a way, that when done together, it becomes hard.
You might make texting much more challenging and meaningful for the game (=requiring actual attention) if you add correct and incorrect options: say, you need to choose correct words from autocomplete suggestions, and if you choose some words (e.g. "moron" in a message to a boss) the game is over.
I would also probably make both driving and texting deadly from "1 hit" (and not 3 hits as it is now), given the other changes I proposed.