The lane was installed on both sides of a 50-meter section from the intersection with Artilērijas to Palīdzības st.
Cyclists appeared to be pleasantly surprised about the lane in widely shared pictures.
A video, claimed to be shot during the rush hour, shows the lane not interfering with motor traffic.
Skaidri redzams, ka vieta pietiek visiem. Brīvības iela sastrēgumu laikā. pic.twitter.com/q1gH3A8ZcJ— oto ozols (@otucis) May 21, 2017
In the late afternoon municipal employees arrived to the scene to remove the lanes.
However, as they set to work cyclists who happened to be passing by started placing their bikes on the lane and obstructing removal.
Aicinam šodien 18:00 visus uz Brīvības ielas velojoslas svētkiem. Apturējām velojoslas dzēšanu, kamēr neuzrādīs dokumentu ar saskaņojumu! pic.twitter.com/PsgGfzxSUw— Māris Kalējs (@mariskalejs) May 19, 2017
In total activists put about a dozen bicycles on the lane before they were taken off by the police. A total four State Police and three Riga Municipal Police vans arrived to the scene to monitor the situation, according to the LETA newswire.
Riga had previously announced grandiose plans for adding bicycle lanes as the number of cyclists in the capital is growing rapidly.
However as the Pilsetacilvekiem.lv urban design website notes, bike lanes spanning just 9 km of the promised 68.8 km have been installed within the last four years.
There was no reaction on the bike lane from mayor Nils Ušakovs (Harmony) ahead of the June 3 municipal elections. However Ušakovs did on May 20 tweet a picture of him carrying an orchestra on a rickshaw on a popular bicycle and pedestrian way by the River Daugava.
Who installed the lanes remains unknown, but the person or persons responsible are facing administrative (misdemeanor) charges should they be caught, reported municipal website Riga.lv.