Metro Vancouver mayors have sent Transportation Minister Todd Stone a letter that  accuses the province of "abrogating its regional responsibility" by not taking a more active role in their transit expansion planning.

The response letter from mayors' council chair Richard Walton to Stone said mayors are concerned about his suggestion last month they delay key rapid transit extensions so their ambitious $7.5-billion expansion plan can be spread out over 20 years instead of 10.

"The option of doing little or nothing in the next 10 years because we cannot come to some agreement on the timing, scope or funding sources will, in our view, have an even greater impact on families, the economy and provincial revenue from the Lower Mainland," it says.

They say the province should instead lobby for more federal contributions to fit their plan's time frame.

The mayors also want the province to clarify whether they could use a vehicle levy, a regional sales tax or new regional carbon tax to fund TransLink now that Stone has ruled out any reallocation of existing carbon tax revenue.

Walton last week told Black Press the mayors may look again at the vehicle levy or sales tax options – if permitted – after concluding a new carbon tax is problematic.

The mayors' letter notes all of the potential sources may run afoul of the province's "somewhat arbitrary and ambiguous" funding source criteria that they be affordable for families, have no negative impact on the economy, be regional in nature and not cut into provincial revenue.

"It would appear that the province has set a standard that is virtually impossible to meet," the letter says.

It also argues the province is inconsistent when it insists those revenue sources be affordable to families but then suggests mayors instead consider raising property taxes, which are an existing TransLink source that can be increased without triggering a referendum.

The transportation ministry said it will work to finalize the date of the expected referendum, which Walton has said would likely be next March.

The province wants the referendum date determined by July 15, while mayors want their questions answered before they meet again July 29.

As for the question to be put to voters, the mayors suggest it be in two parts – the first asking voters to indicate their support for the proposed 10-year investment plan, while the second would ask their support for one or more new revenue sources.

Metro mayors continue to assert that they do not believe the transit plan and new taxes to fund it should be submitted to a referendum, arguing that is "not sound policy."