At a mayoral forum on environmental issues last night, Republican candidate Taubenberger jokingly suggested that they should go for a ride on a bicycle built for two.
"We spend more than enough time together," Democrat Nutter shot back, as the audience laughed.
The usually agreeable rivals fielded questions on topics including recycling, funding the park system and reducing greenhouse-gas emissions during the forum at the Academy of Natural Sciences. Sponsors of the event were the Pennsylvania Horticultural Society, the Next Great City project and the Urban Sustainability Forum.
Many of the questions were submitted via YouTube, as in some recent presidential debates.
The candidates agreed that the city needs to invest more in sustainability, although Nutter's responses were more detailed.
Nutter said he would try to make Philadelphia the "Number One green city in the United States of America." He pledged to reduce the city's energy costs by 10 percent, plant hundreds of thousands of trees and conduct a massive citywide cleanup effort, if elected.
"I think the most revealing thing I've found in the course of running around this great big city is how dirty it is," he said.
Taubenberger said he would like to put a rooftop garden on City Hall and put gardens in vacant lots.
"If they're vacant, let's make use of them," he said.
Nutter and Taubenberger also appeared together yesterday at a health-care forum at the College of Physicians, where both pledged to devote more resources to public health, encourage the public to lead healthy lives and better promote Philadelphia as a medical center.
Nutter also revealed a bit of his own medical history, noting that his last blood-pressure check was "excellent" at 120/80.
"I think I'm going to make it through the rest of the campaign," he said.