Crews this week began painting parking boundaries and shared bike lanes in the 4700 block of North Milwaukee Avenue. View Full Caption DNAinfo/Alex Nitkin

PORTAGE PARK — Crews have begun painting bicycle lanes along a two-mile stretch of Milwaukee Avenue spanning the Old Irving Park and Portage Park neighborhoods, fulfilling a long-held priority of city transportation officials and Ald. John Arena (45th).

By the end of May, half the on-street parking will disappear along the avenue between Addison Street and Irving Park Road, making way for buffered bike lanes in both directions, according to Arena's office.

The lanes were the top vote-getter in the ward's 2015 participatory budgeting process. That same year, a study commissioned by the city's transportation department found that parking lanes along the half-mile route are rarely more than one-quarter filled with parked cars, according to Owen Brugh, Arena's chief of staff.

Transportation officials "believed there was more than twice as much parking as was needed along that stretch, so they thought it was prudent to remove those spots," Brugh said. "Milwaukee is a major bicycling street through the city, and this addition will make a significant connector in the the city's bicycling network."

A diagram showing which on-street parking spots will be removed from Milwaukee between Addison Street and Irving Park Road [Chicago Department of Transportation]

On the longer section of Milwaukee connecting the Six Corners Shopping District to the Jefferson Park Business District at Lawrence Avenue, fresh parking boundaries and "sharrow" symbols will sketch out "marked shared lanes" guiding a path for cyclists without removing any existing parking spots, Brugh said.

Once the paint job is completed, bike lanes will trace Milwaukee from Addison all the way up to Devon Avenue in Norwood Park.

While welcome news for cyclists, the coming changes aren't without critics.

The parking lanes will be sorely missed by employees and patrons of Portage Auto Parts, 3920 N. Milwaukee Ave., salesman Neil Prodoehl said.

"All our customers park out front," Prodoehl said. "And if we lost that, then whenever we got a new shipment, the delivery truck would have to come around back on Byron [Street] and block people. That would suck."

Neil Prodoehl, a salesman at Portage Auto Parts, 3920 N. Milwaukee Ave., said the business would be ill-served by removing on-street parking. [DNAinfo/Alex Nitkin]

The new lanes come three years after Arena backed a "road diet" for Milwaukee Avenue along the Gladstone Park corridor, which would have narrowed traffic to one lane in each direction and installed protected or buffered bicycle lanes. But the plan drew scathing criticism from constituents who worried that removing parking spots would snarl traffic and hurt neighborhood businesses, and Arena dropped the plan.