Philadelphia's proposal to improve bike safety on Spruce and Pine Streets in Center City got a public hearing this week, and took flak from people who argued it did too much or not enough.

If City Council approves, this fall the city will swap bike and parking lanes to opposite sides on Spruce and Pine from Front to 22nd Streets. The shift is part of an overall strategy to relocate bike lanes to the left side of streets, which officials have said makes riding safer.

The change is happening along with scheduled street paving, but gained attention after 24-year-old Emily Fredricks was killed in November by a truck as it made a right turn across a bike lane while she was riding on Spruce. The accident remains under investigation, police said.

The proposal was met with complaints at the meeting at the University of the Arts on Broad Street on Thursday.

Some in the affected area were dismayed the plan didn't go further in making the streets safer for bikes and pedestrians. Much of the focus at the meeting was on the dangers of truck blind spots. Some asked if trucks could be restricted from deliveries on those streets so they didn't coincide with high travel hours. There was also concern that there wasn't a more definite plan for loading zones, where they would be, and if there would be an effort to limit when they could be used.

"That's part of the problem with this, that there are a lot of things that have been talked about that haven't been changed," said Judy Applebaum, a member of the Washington Square West Civic Association.

Bike safety advocates, meanwhile, lamented that the city didn't do more to create protected bike lanes.

"That is disappointing to me," said Leigh Goldenberg, a biker who is active in lobbying for protected bike lanes. "I feel like if all of this effort is going in to take a half-measure, it's going to take a whole decade to get that done."

Relocating loading zones would be managed with the Philadelphia Parking Authority, city officials said. Deciding whether to limit truck access on those streets may be addressed in the future.

"What happens to the businesses that are located on Pine and Spruce Streets that need to receive deliveries? We're in those discussions," said Mike Carroll, the city's deputy managing director for transportation.

The switch is expected to minimally reduce the number of available parking spaces, city officials have said.

Switching the lanes will require intersection adjustments to make turning left safer for cyclists. The city is considering three models, with options that include delineators between car and bike lanes. Bikes can make right turns by crossing the street to the opposite side of the intersection, and then crossing to the right.

The Federal Highway Administration recommends bike lanes be installed on the right side of a street unless, on a one-way street, there are frequent bus stops, high numbers of vehicles making right turns, or a lot of cyclists turning left. City officials have said they believe Spruce and Pine Streets' locations near the heart of Center City mean cyclists likely turn in either direction off them in equal numbers.

One of the great benefits of a left-side bike lane, city officials and cycling advocates said, is that vehicles, particularly trucks, have larger blind spots on their right than on the driver's side. Studies have shown those blind spots result in more crashes on a vehicle's right than on the left. Trucks were involved in crashes while making lane changes or merging 4.4 times more frequently on the right than on the left, a 2007 University of Michigan study that looked at the value of mirrors on trucks found. That study also found right turn crashes were "significantly more frequent" than left turn crashes.

The proposal for the lane switch has already raised opposition from the Society Hill Civic Association, which commissioned its own street study for the Society Hill neighborhood and noted shifting lanes was not cited as a priority on streets that rarely have high-speed traffic on them.

Spruce and Pine Streets carry a total of 500 to 1,000 cyclists a day, officials from the Bicycle Coalition of Greater Philadelphia have said. An analysis that group performed on crash data from 2009 to 2016 found that 61 percent of crashes on the two roads happened with vehicles at an angle, meaning the vehicle was likely making a turn.

Amid the complaints were those who appreciated the simple infrastructure upgrade.

"You can't see the lanes and that's what's killing me," said Lauren Powers, who bikes in the area from her home in East Passyunk. "I'm just excited we're getting new striping."

Also positive about the change were Fredricks' parents, who attended Thursday.

"If this is really making this safer, that's the whole point of this," her mother, Laura, said. "They're not doing it to inconvenience you."