The congestion that brought the Massachusetts Turnpike to a standstill on the Sunday after Thanksgiving was yet another reminder that the state’s main east-west artery is always an accident or breakdown away from gridlock. That raises an obvious question: What would the overburdened highway look like if casino traffic were added to the mix?

Many of the casino plans taking shape in central and western Massachusetts would add new strains to the Pike, and the state casino commission vetting applications has properly vowed to ensure that any resort won’t worsen traffic. The Pike runs just past Springfield, where local officials have been touting the highway’s proximity as a key advantage. Another possible casino site, in Palmer, sits next to the Pike and close enough to the junction with Interstate 84 — the very intersection that was ground zero for traffic snarls last Sunday — to worry regular users of the highway.