Commuters were in for a surprise Tuesday morning as crews began work on 923 N. Michigan Avenue – the intersection before traffic enters and exits Lake Shore Drive – causing a bottleneck and consequent delays.

The work was the result of an emergency sewer repair for the intersection of Walton Street and Michigan Ave., according to a city permit.

The right-of-way permit filed with the Chicago Department of Transportation, the work required the closure of a northbound left turn lane and one southbound through lane on Michigan Ave., and a westbound left turn lane and one through lane on Walton St., according to the permit’s description.

The construction appeared to have an effect on commuters exiting Lake Shore Drive, but was especially acute for CTA’s express buses that exit the Drive from the North Side. Some of those routes include the #146, #147 and the #151 to name a few.

One commuter, Megan Abel, took to Twitter Tuesday morning with a post:

Who came up with the brilliant idea of starting construction at the peak of rush hour right at lake shore drive and michigan ave?

— Megan Abel (@legothatmego) June 4, 2013

There were no commute warnings issued by Chicago Transit Authority and the Chicago Department of Transportation.

Spokespersons for the CTA and CDOT said they were looking into the construction, but were not able to reply back readily.

Also unavailable was a timetable for the construction. But according to the city’s data portal site, the permit for the work was extended just yesterday to 6/21/13, with work hours being Monday - Friday only between the hours of 7:00 a.m. to 7:00 p.m.