I'll start by saying I have taken ONE 1 hour break in the last 13 years. They announced at the morning meeting we had to take an hour break. That day I did. Luckily, the next morning we had a meeting with our Director. I asked, in front of everyone including the managers, 'We were told we needed to take an hour break. Has the policy changed, or can we still take 30 minutes?' Her, response 'No, the policy hasn't changed. You can still take only 30 minute, if you want'. Managers faces turned red.
It's also my understanding (not sure if it's accurate), it depends on state law. But, according to FMCSA, you can only take 30, if you choose. You can read that here
Summary of Hours of Service Regulations | FMCSA