Yes, suggested Advocate General Bot in Federación de Servicios Privados del sindicato Comisiones Obreras.
According to the Advocate General, there are three aspects to 'working time': being (1) at the workplace, (2) at the disposal of the employer, (3) engaged in work duties (C-151/02 Jäger).
For peripatetic workers: aspect (1) was fulfilled because travelling is an integral part of the job, such that the workplace cannot only be considered as performing work at clients' premises; aspect (2) was fulfilled because routes and destinations are determined by the employer who could at any point modify the instruction; and aspect (3) was fulfilled because, again, travelling is integral to the peripatetic work.
The Advocate General saw no distinction between travel between jobs, which was agreed to be working time, and to and from the first and last jobs, which was not. Further, since working time and rest time are mutually exclusive concepts, and in line with CJEU case law (C-303/98 Simap) rest time must not involve obligations vis-à-vis the employer, the travel time had to be working time.
The recommendation of the Advocate General is not binding, but it is usually followed by the ECJ.