North Fulton cities are wasting no time getting plans back on track for a new $16 million emergency radio system to replace the current network operated by Fulton County.

One week after Johns Creek bowed out, city councils in Alpharetta, Roswell and Milton voted Monday night to proceed with the project. Sandy Springs is scheduled to vote on the agreement at a special meeting Wednesday.

The new agreement calls for each city to pay a bigger share of the cost than originally planned, absorbing the $2.7 million Johns Creek was scheduled to pay. Shares are based on a city’s size, population and number of radios.

“This is obviously a significant increase from what we had when Johns Creek was involved,” Roswell City Councilman Rich Dippolito said. He said he’d like to see the Roswell recoup that extra cost if Johns Creek later decides to join the system as a subscriber.

Fulton County’s emergency radio system — the network that allows police, fire and ambulance communication — is 20 years old and has experienced occasional failures in recent years.

City leaders in Johns Creek had initially signed on to join the other north Fulton cities but became wary when Motorola was named to supply equipment for the bulk of the system. City leaders said all the equipment should have been put out for competitive bid.

Sandy Springs, the procurement agent for the coalition, said Motorola has offered a discount over its bid price listed for state contracts, which have already passed the competitive bidding process.

Without Johns Creek in the mix, Alpharetta will now pay$3.7 million, about $700,000 more than before. Milton will pay$2.4 million, about $400,000 more. Roswell will pay $5.1 million, about $900,000 more, and Sandy Springs will pay$4.7 million, about $800,000 above the original proposal.

Johns Creek city leaders say they plan to work with Fulton County as it proceeds with its own plan to replace the current radio system.