The government has submitted a bill to the State Duma that would boost fines and introduce prison terms for protesters who block roads.

Hundreds of unpaid workers blocked a highway in the Leningrad region town of Pikalyovo in June, prompting Prime Minister Vladimir Putin to fly into the town and force factory owners, including billionaire Oleg Deripaska, to pay wage arrears.

A demonstrator who blocks a road would be punished by a fine of up to 100,000 rubles ($3,370), a fine equal to six months of his wages, or up to two years in prison, according to the bill posted on the Duma’s web site.

The law currently imposes a punishment of up to 1,500 rubles ($50) for an individual who “intentionally disturbs road traffic.”

The bill also introduces a fine of up to 80,000 rubles ($2,690) for transportation officials who fail to prevent an accident on public transportation that causes serious injuries or property damages of more than 500,000 rubles ($16,830).

A transportation official could be imprisoned for up to five years if the accident killed one person and up to seven years if it killed two or more people.

The bill was drafted in part as a response to “the growing threat of terrorist acts” on public transportation and on public transportation links, the government said in a note attached to the bill.

A bomb explosion derailed the train Nevsky Express in late November, killing 27 people.

The bill was submitted Thursday, the Duma’s web site said. A date for the first reading of the legislation hasn’t been set.

The bill is the state’s latest initiative to prevent protests after several major roads were blocked by angry workers this year. The protests have stirred the Kremlin’s fears of social unrest amid the economic crisis, and President Dmitry Medvedev has warned governors that they face dismissal if they don’t keep protesters away from major roads.