TAMPA — Harry Cohen stood before several hundred people at the Tampa Museum of Art on Wednesday evening with a simple message: He's a proven quantity that residents can rely on to take the city to the next level — and do it fairly.Cohen, a two-term City Council member, painted a portrait of a city on the rise that he helped nurture.The Riverwalk's maturation into a municipal gem, new parks, and, in a nod to his South Tampa district, an aggressive fix to the chronic flooding in those neighborhoods, he said, were all accomplishments he helped make happen while serving on the council and in partnership with outgoing Mayor Bob Buckhorn."We are becoming the city we have always dreamed of being," Cohen said in a 10-minute speech.As for the future, Cohen promised to tackle the city's transit problem by embracing new technologies, leapfrogging the deteriorating systems of other cities into a future that makes the city more efficient and safer."I know how to dream big and high and I know how to get things done," the 48-year-old Cohen said.Without directly mentioning the recent pedestrian deaths on Bayshore Boulevard, Cohen said the city has to be made safer for bikers and pedestrians, but added that everyone has to make smart decisions."In addition to what government can do to make our streets and sidewalks safer — and we can do a lot — we have to look out for each other, take care of each other and make sure that our own individual actions are worthy of our community," Cohen said.Balancing Tampa's growth while maintaining its quality of life will be perhaps the biggest challenge ahead, Cohen said. But he added that a booming Tampa can't ignore its struggling neighborhoods."Not everyone experiences Tampa in the same way," he said, "And it is unacceptable for some areas of the city to thrive while others are left behind."Cohen is the fourth mayoral candidate to have a formal kickoff in front of donors, supporters and the simply curious as campaigns aim to make a good first impression among voters.Small businessman Topher Morrison, former county commissioner Ed Turanchik and former police chief Jane Castor have already held events since mid-March, an earlier start than usual for the city's biggest political prize.Council member Mike Suarez and retired banker and philanthropist David Straz have also announced that they're running.Cohen closed his pitch with a nod to his reputation as a fair-minded politician:"You know me. You know that I make myself available. That I respond. And that I am effective in bringing people together and getting things done."