Heavily regulated Boston cab owners last week filed a federal lawsuit against city and state regulators they charge have put them at a competitive disadvantage by letting Uber, Lyft and similar concerns steal their business.

In their lawsuit, filed in US District Court, the Boston Taxi Owners Association and two individual medallion owners charge the city is ruining their investments in expensive medallions by letting ride-share or "transportation network companies" pick up passengers for hire without any similar investment.

Medallion owners have to comply with expensive safety, licensing and insurance regulations, while any jamoke with a car - even one with a potential criminal background - can pick up fares through these competitors, the suit says, charging this violates the equal-protection clause of the Fourteenth Amendment.

And don't even get the cab owners started on a regulation proposed by outgoing Gov. Deval Patrick, which they say would deprive them of their rights under the due-process clause by essentially eliminating a cap on medallions, thereby "irrationally destroying" the value of those medallions.