[2] In 1971, Hahlweg was the SPD's first candidate for the office of Lord Mayor of Erlangen, losing out to Heinrich Lades with 48.1% of the votes.

Above all, the consistent promotion of utility cycling earned Erlangen the reputation of a bicycle city.

But also other measures of Dietmar Hahlweg, such as the modernisation of the sewage treatment plant, the expansion of the district heating and natural gas networks and the direct feeding of solar power into the network of the municipal utilities, led to Erlangen's inclusion in the UN list of honour "Global 500" and to the award of the title "Federal Capital for Nature and Environmental Protection" by the Environmental Action Germany both in 1990 and 1991.

[6] The Social Democrat Hahlweg also endeavoured to support Willy Brandt's Ostpolitik at local level.

This included events such as "Encounter with Poland" (1976) or the start of negotiations on a town twinning with Vladimir in the then Soviet Union.

He has been a Knight of the French Legion of Honour since 1991 and was awarded the Federal Cross of Merit 1st Class in 1993.

(Raphael Wünsch, 1996)[8] Dietmar Hahlweg became nationally known through the Erlangen fun metal band J.B.O., because he is mentioned in their song Der Weiße Hai im Dechsendorfer Weiher.