TriMet will soon have the authority to ban violent offenders from the transit system for more than six months, and in some cases permanently.

The agency's governing board approved the new ordinance on Wednesday. It will take effect in 30 days.

Under its own code, the agency was historically able to ban riders for no more than six months. That policy was intended to ensure transit-dependent riders weren't permanently kept from using the public system.

The new policy carves out an exception for riders who commit a "serious physical offense" or pose a threat to TriMet employees or riders.

The agency's general manager will have the authority to ban first-time offenders for up to a year, and impose as much as a lifetime embargo for subsequent offenses.

Prohibited riders will be allowed to appeal their exclusion to the agency once a year.

The new policy was prompted largely by the case of Jared Walter, known as the "TriMet Barber" for his repeated arrests since 2009 for cutting or masturbating in women's hair aboard buses.

He most recently was arrested in May after he was again seen cutting a woman's hair on a bus.

It also comes two and a half months after a stabbing about a MAX train in May left two men dead and critically injured another, and as the agency seeks to respond to cases of assault and intimidation against its operators and other employees.

The long-term bans, however, won't be applied to Walter or Jeremy Christian, the suspect in the May stabbing, unless they offend again. TriMet spokeswoman Roberta Altstadt said they can't be instituted retroactively.

-- Elliot Njus

enjus@oregonian.com

503-294-5034

@enjus