here isolines

isa.py

from creds import ID,CODE       # isolines: driving from my house

import folium
import requests

home =[-33.406654,-70.572701]     # 085 LOS MILITARES / ALONSO DE CORDOVA
head = 'https://isoline.route.cit.api.here.com/routing/7.2/calculateisoline.json?'
URL_BASE = '{}app_id={}&app_code={}&mode=shortest;car;traffic:disabled&start=geo!{},{}&range={}&rangetype={}'

def isodata(home, range, type):
	url = URL_BASE.format(head, ID, CODE, home[0],home[1], range, type)
	js = requests.get(url).json()['response']
	center = js['center']	# {'latitude': -33.406654, 'longitude': -70.572701}
	iso = js['isoline']
	comps = [(float(x.split(',')[0]),float(x.split(',')[1])) for x in iso[0]['component'][0]['shape']]
	return comps
	
fm = folium.Map(location = home, zoom_start=13, tiles='CartoDBPositron')
for time, color in zip([60,300,600],['green','blue','red']):	# 1,5,10 min
	isoline = isodata(home, time, 'time')		
	folium.PolyLine(locations=isoline,color=color).add_to(fm)
fm.save('maida.html')

full ref here: https://developer.here.com/documentation/routing/topics/request-isoline.html

import branca.colormap as cm
colormap = cm.linear.Set1.scale(0, 30).to_step(5)
colormap.caption = 'A colormap caption'
fm.add_child(colormap)

All APIs listed here
Modes can be publicTransport, bicycle...

Great example! Still works in 2018.
If you add the following code, it will even take into account the traffic situation in the rush hour time (in this example 2018-08-07T08:00:00 considered to be a time of high traffic - the start of working hours on a working day.)
&mode=fastest;car;traffic:enabled&departure=2018-08-07T08:00:00.

Works also with the free plan.