David Yashar was one of many drivers caught in a recent, late afternoon traffic jam caused by a pickup truck fire on the Massachusetts Turnpike. As a result, he said, he has lost faith in the value and reliability of the traffic notification system run by the state’s Transportation Department. Frustrated with the lengthy delay and wondering what exactly was going on, Yashar searched on the state-run 511 hotline and the mass511.com website, which purport to offer real-time traffic updates, hoping for some useful information. And as he progressed, he scanned the electronic message board he passed but saw nothing posted.