When city-planners and government officials in Alabama set out to improve Birmingham’s rough edges, historic Avondale was the perfect starting point. A company town in the 19th century, the area had since turned into a desolate corner of the city. Yet its transformation began almost five years ago with a $2.8m (€2.4m) revitalisation of Avondale’s park and amphitheatre.

“The park revamp kick-started everything and it has become a rapidly growing entertainment district,” says chief city-planner Tom Magee. The neighbourhood is now a thriving nightspot filled with restaurants and bars, which has in turn been a draw for other businesses. At the start of the renovation, commercial vacancy in the area was 75 per cent. Now more projects are in the works than ever before and vacancy for 2016 has hit an all-time low of 2 per cent.

With business concepts such as Box Row – a $4.3m (€3.8m) initiative that will house 39 shops and 12 offices – opening in the coming months, urban-planners expect Avondale to expand more this year. “We want Box Row to be a place for people to shop, eat, drink and hang out from day to night,” says Robert Ferrara, project leader and principal of Blue Oak Development, the company behind the plans.

Growing new businesses and filling vacant spaces through the district’s linear corridor – the six city blocks of 41st Street South – has always been the mission. “It became clear that Avondale had an opportunity to carve out a defining niche around entertainment innovation and entrepreneurship; it took off and the vacant spaces began to fill up,” says David Fleming, chief executive of Rev Birmingham, a business-development organisation.

With an energetic daytime agenda and nightlife, the neighbourhood has become a vibrant destination for food, drink, concerts and events, meaning ever-increasing visitor numbers and continued economic revitalisation.

Los Angeles has been proving that there is more to its transport system than clogged-up highways. May’s expansion to the metro’s Expo Line – a $1.5bn (€1.3bn) light-rail line that now links Downtown with the golden beaches of Santa Monica – was greeted with much fanfare by Angelenos. But is it part of a move towards a more public-transport friendly future?

There are some auspicious indicators: this summer, downtown LA will get its first cycle-share system with a roll-out of 1,000 new bikes docked at 65 solar-powered stations. Meanwhile major infrastructural developments such as Downtown’s regional connector, opening in 2021, will enable passengers to traverse much of the Los Angeles basin by train. LA clearly has an eye on its 2024 Olympics bid – not that those packed highways are about to disappear overnight.

Leah Treat, who has worked for transport agencies in Chicago and Washington, now leads one of the most lauded urban mass-transit systems in the US.

Why come to Portland?
It has the most progressive transport policies in the US. Decades ago people here were thinking about limiting sprawl and building light rail and trams – ideas that other places in this country weren’t exploring at the time.

How has the city changed since your appointment?
Portland is experiencing the most rapid population and business growth in its history; there’s essentially no more road space to build in the city. We’re working to get more people on mass transport, new bus rapid transit lines and a new light-rail line. We’re also trying to connect protected cycling tracks into a network.

What’s the positive side to the growth?
Statistically people who have moved here since 2000 take many more trips via bicycle and work from home more often. If the new Portlanders travelled in the same way that the existing population does, traffic would have skyrocketed. When people make a major life change – such as moving to a new city – we’ve seen clearly that it’s a moment to persuade them to make other changes.

Cycle-sharing launches in Portland in July. How will that improve matters?
It will be a very affordable – and fun – way to navigate the city and it should reduce car traffic. If, for example, you’re coming to the city centre for work but know that at midday you have a doctor’s appointment, right now you might drive a car. Once cycle-share launches maybe you’ll take transport into the city and then ride to the appointment.