The opponents of motorists' party predict that adding a bicycle lane to the Blue High way will reduce rush-hour traffic by encouraging residents to use their bicycles. This argument is flawed because of several groundless assumptions.
First, the author claims that because the additional lane compounded traffic jam on Green Highway, it will compound traffic on Blue Highway, too. However, he fails to provide any justification that two Highways are similar in terms of number of lanes, the places they connect, the population of the area, number of commuters, the quality of highways and so on. For one, the area near the Green Highway may have larger population, and adding an extra lane encouraged more people to use their private vehicles. Moreover, maybe something else worsened the traffic jam on Green Highway, for example, construction on the nearby roads, lack of appropriate driving signs, or increase of commuters because of a new factory or housing estates in the area. The stated comparison without regarding total conditions of the highways is invalid, and the author should provide more information based on a comprehensive investigation to make it convincing.
Second, the addition of a lane and subsequent increase in traffic jam on Green Highway dates back to one year ago. Many things might have changed since then, for instance today people are maybe more willing to use public transportation because of high cost of fuels or more efficient public transportation, so maybe adding a lane to Blue Highway will not attract more commuters to use this highway. The author needs to prove that if such influential parameters have not changed since last year.
Third, even if above assumptions are true, adding a cycling lane will not necessarily attenuate the traffic congestion on Blue Highway. That the area residents are keen bicyclists that does not mean that they will certainly use bicycles for their daily and exhausting commutes between suburbs and the city center specially if this distance is considerably long. Maybe they are keen on cycling for recreation. Besides, it is a matter of question whether traveling by bicycle will reduce the residents' current commuting time, which was the primary reason for suggesting a bicycle lane. On the other hand, are majority of the commuters of Blue Highway from the area and interested in cycling? The argument would have been stronger had it provided more information regarding the distance between the city center and suburbs, and willingness of commuters.
To sum, the author fails to provide a forceful argument that widening the highway will increase the traffic, and, in contrast, a bicycle lane will encourage the residents, successively reduce the traffic and commuting time.