The greatest disfigurement of the residence street is found in the varied assortment of poles which crowd out the trees along the space between curb and sidewalk. There are trolley-poles, electric lighting poles, poles for telephone wires, and poles for police and fire-alarm purposes. The natural development of the city will relegate the greater portion of such service into conduits controlled by the municipality and occupied in common by the city and the various public service corporations. So fast as streets are cleared from these obstructions, the municipality should take over the planting and maintenance of all trees in street spaces; so that the planting may be effective and attractive throughout the entire way. The present method of leaving such work to individuals necessarily results in a ragged appearance of the street, and also fails to provide that diversity in variety of trees which gives beauty and individuality to the thoroughfare. The avenue or traffic street should be of sufficient width to draw to itself the streams of traffic passing from one point in a city to distant points. Provision should here be made not only for vehicular traffic, but also for street-car lines; and the two currents may well be separated, so as to avoid interference with each other. This end may be obtained as in Paris by a road lined with trees, or there may be subdivision into various roadways, of which one is dominant. These thoroughfares, when conforming to the rectilinear street system, should be developed at intervals sufficiently frequent to accommodate the traffic that naturally would be drained into them from the narrower parallel streets and from the intersecting streets. In order, however, to care for the traffic which flows from northeast to southwest, and from northwest to southeast, and vice versa, diagonal avenues become a necessity, in order to save time and consequent expense.