Here is what Texas law has to say about impediment in general,

Sec. 545.363(a).  MINIMUM SPEED REGULATIONS.  An operator may not drive so slowly as to impede the normal and reasonable movement of traffic, except when reduced speed is necessary for safe operation or in compliance with law.

There is mention of the responsibilities of cyclists with respect to impeding the normal and reasonable flow of traffic. However the context differs from that which most might believe.

Sec. 551.103(c).  OPERATION ON ROADWAY. Persons operating bicycles on a roadway may ride two abreast. Persons riding two abreast on a laned roadway shall ride in a single lane. Persons riding two abreast may not impede the normal and reasonable flow of traffic on the roadway.

In fact, the Texas Transportation Code excepts consideration of a bicycle operating in a vehicular manner as an impediment with the following language,

Sec. 551.101(a)(2).  RIGHTS AND DUTIES.  A person operating a bicycle has the rights and duties applicable to a driver operating a vehicle under this subtitle, unless a right or duty applicable to a driver operating a vehicle cannot by its nature apply to a person operating a bicycle.

Bicycles are defined as vehicles. Physical and physiologic limitations make it all but impossible for a cyclist to maintain a velocity much above 35kph. The average is closer to 25kph. If the operator of a bicycle is making effort, to the best of their ability, to travel at a reasonable speed, there is no impediment. A notable exception being those conduits which have a minimum posted speeds, but those are few and far between. Otherwise, the law and reasonable accommodation favor the cyclist.

Similar analyses have been shared by other competent, experienced vehicular cyclists. Mighk Wilson did so in May and couched it under the same statutory framework. An earlier example includes a piece written by Bob Mionske, in 2006, responding to correspondence he received from a Minnesota cyclist in VeloNews. The simple fact is that cyclists cannot be guilty of impeding other traffic so long as every attempt is made to maintain a reasonable pace and accommodate the needs of other vehicles to the extent that is safe and logical. As a legally recognized vehicle, bicycles have the same rights and responsibilities as any other operator.